HRS DOCUMENTATION RECORD COVER SHEET

Name of Site: Smurfit-Stone Mill

EPA ID No. MTN000802850 

Contact Persons

Site Investigation: Robert Parker (303) 312-6664 

 Site Assessment Manager

U.S. Environmental Protection Agency, Region 8 

1595 Wynkoop Street, Mail Code: 8EPR-AR

 Denver, Colorado 80202-1129 

Documentation Record: Sabrina Forrest (303) 312-6484 

 National Priorities List Coordinator

U.S. Environmental Protection Agency, Region 8 

1595 Wynkoop Street, Mail Code: 8EPR-AR

 Denver, Colorado 80202-1129 

Jeff Miller (303) 291-8212 

 Senior Environmental Scientist 

URS Operating Services 

999 18th Street, Suite 900

 Denver, Colorado 80202 

Pathways, Components, or Threats Not Scored 

The soil exposure, ground water, and air migration pathways were not scored as part of this Hazard 

Ranking System (HRS) evaluation. The soil exposure, ground water, and air migration pathways were not 

scored as part of this evaluation because the surface water migration pathway produces an overall site 

score above the minimum required for the site to qualify for inclusion on the National Priorities List 

(NPL).

These pathways may be of concern to EPA and may be evaluated during future investigations.

The surface water overland/flood migration component is not scored for the Smurfit-Stone Mill site. The 

ground water to surface water migration component, environmental threat and food chain threat produces 

an overall score above the minimum required for the site to qualify for the NPL.
1 

HRS DOCUMENTATION RECORD

Name of Site: Smurfit-Stone Mill

Date Prepared: May 2013 

EPA Region: 8 

Street Address of Site*: 14377 Pulp Mill Road

City, County, State, Zip: Missoula, Missoula County, Montana, 59808

General Location in the State: Western-central portion of state, in the Clark Fork River watershed

Topographic Maps: Primrose, Montana 7.5 minute topographic map, 1963 (Photorevised 

1978) (Ref. 71, p.2)

Latitude: 46.957781° North

Longitude: 114.199623° West 

Site Reference Point: The coordinates above were measured from source sample location 

SSSO0502, collected within Source No. 1 of this HRS 

documentation record (Ref. 5, Figure 2 (p. 67), Figure 4 (p. 69); 

Figure 1 of this HRS documentation record) 

*The street address, coordinates, and contaminant locations presented in this HRS documentation record 

identify the general area the site is located. They represent one or more locations EPA considers to be part 

of the site based on the screening information EPA used to evaluate the site for NPL listing. EPA lists 

national priorities among the known “releases or threatened releases” of hazardous substances; thus, the 

focus is on the release, not precisely delineated boundaries. A site is defined as where a hazardous 

substance has been “deposited, stored, disposed, or placed, or has otherwise come to be located.”

Generally, HRS scoring and the subsequent listing of a release merely represent the initial determination 

that a certain area may need to be addressed under CERCLA. Accordingly, EPA anticipates that the 

preliminary description of facility boundaries at the time of scoring will be refined as more information is 

developed as to where the contamination has come to be located. 

Pathway Pathway Score

Air Pathway Not Scored

Ground Water Pathway Not Scored

Soil Exposure Pathway Not Scored

Surface Water Pathway 100.00 

HRS SITE SCORE 50.00
2 

WORKSHEET FOR COMPUTING HRS SITE SCORE

 S S2

 

1. Ground Water Migration Pathway Score (Sgw) Not Scored Not Scored

2a. Surface Water Overland/Flood Migration Component (Sof) Not Scored Not Scored

(from Table 4-1, line 30) 

2b. Ground Water to Surface Water Migration Component (Sgs) 100.00 10,000 

(from Table 4-25, line 28)

2c. Surface Water Migration Pathway Score (Ssw) 100.00 10,000 

Enter the larger of lines 2a and 2b as the pathway score.

3. Soil Exposure Pathway Score (Ss) Not Scored Not Scored

(from Table 5-1, line 22) 

4. Air Migration Pathway Score (Sa) Not Scored Not Scored

(from Table 6-1, line 12) 

5. Total of S 2 2 2 2

gw + Ssw + Ss + Sa 10,000 

6. HRS Site Score 50.00 

Divide the value on line 5 by 4 and take the square root

 
3 

HRS TABLE 4-25 --Ground Water to Surface Water Migration Component Scoresheet

Factor Categories and Factors Maximum

Value

Value

Assigned

Drinking Water Threat

Likelihood of Release:

1. Observed Release 550 550

2. Potential to Release:

2a. Containment 10 NS

2b. Net Precipitation 10 NS

2c. Depth to Aquifer 5 NS

2d. Travel Time 35 NS

2e. Potential to Release (lines 2a x [2b + 2c + 2d]) 500 NS

3. Likelihood of Release (higher of lines 1 and 2e) 550 550

Waste Characteristics:

4. Toxicity/Mobility/Persistence (a) NS

5. Hazardous Waste Quantity (a) NS

6. Waste Characteristics 100 NS

Targets:

7. Nearest Intake 50 NS

8. Population:

8a. Level I Concentrations (b) NS

8b. Level II Concentrations (b) NS

8c. Potential Contamination (b) NS

8d. Population (lines 8a + 8b + 8c) NS

9. Resources 5 NS

10. Targets (lines 7 + 8d + 9) (b) NS

Drinking Water Threat Score:

11. Drinking Water Threat Score

maximum of 100)

([lines 3 x 6 x 10]/82,500, subject to a 100 NS

Human Food Chain Threat

Likelihood of Release:

12. Likelihood of Release (same value as line 3) 550 550

Waste Characteristics:

13. Toxicity/Mobility/Persistence/Bioaccumulation (a) 5 x108

14. Hazardous Waste Quantity (a) 1 x 106

15. Waste Characteristics 1,000 1,000

Targets:

16. Food Chain Individual 50 45

17. Population:

17a. Level I Concentrations (b) NS
4 

Factor Categories and Factors Maximum

Value

Value

Assigned

17b. Level II Concentrations (b) 0.03

17c. Potential Human Food Chain Contamination (b) NS

17d. Population (lines 17a + 17b + 17c) (b) 0.03

18. Targets (lines 16 + 17d) (b) 45.03

Human Food Chain Threat Score:

19. Human Food Chain Threat Score ([lines 12 x 15 x 18]/82,500, 

subject to a maximum of 100) 100 100.00 

Environmental Threat

Likelihood of Release:

20. Likelihood of Release (same value as line 3) 550 550

Waste Characteristics:

21. Ecosystem Toxicity/Mobility/Persistence/Bioaccumulation (a) 5 x107

22. Hazardous Waste Quantity (a) 1 x 106

23. Waste Characteristics 1,000 1,000 

Targets:

24. Sensitive Environments:

24a. Level I Concentrations (b) 0

24b. Level II Concentrations (b) 75

24c. Potential Contamination (b) NS

24d. Sensitive Environments (lines 24a + 24b + 24c) (b) 75

25. Targets (value from 24d) (b) 75

Environmental Threat Score:

26. Environmental Threat Score ([lines 20 x 23 x 25]/82,500, subject to 

a maximum of 60) 60 60.00 

Ground water to Surface Water Migration Component Score For A 

Watershed

27. Watershed Scorec (lines 11 + 19 + 26, subject to a maximum of 100) 100 100.00

28. Component Score (Sgs)

c

, (highest score from line 27 for all 

watersheds evaluated, subject to a maximum of 100) 100 100.00 

Notes:

a Maximum value applies to waste characteristics category b Maximum value not applicable c Do not round to nearest integer

NS Not scored
5

REFERENCES

Ref.

No. Reference description 

1. U.S. Environmental Protection Agency (EPA), Hazard Ranking System (HRS), 55 Federal 

Register 51532. December 14, 1990. Excerpt. Cover page only. A complete copy is available at: 

http://www.epa.gov/superfund/sites/npl/hrsres/index.htm and in the Region 8 Docket. [1 

page]

2. EPA. Superfund Chemical Data Matrix (SCDM). Updated March 31, 2012. Excerpt. A complete 

copy of SCDM is available at: http://epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm [29 

pages]

3. EPA. 2012. Superfund Site Information. Smurfit-Stone Mill. Data extracted September 19, 2012. 

Accessed online at: http://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0802850 Accessed 

September 19, 2012. [1 page]

4. EPA-START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist to SmurfitStone Mill HRS project file, regarding methodology and source data used to create figure 

entitled: M2 Green Redevelopment LLC Properties (Formerly Smurfit-StoneMill). Dated January 

3, 2013. [4 pages] 

5. EPA-START. 2012. Analytical Results Report for a Combined Site Inspection and Removal 

Assessment. Smurfit-Stone Mill, near Missoula, Missoula County, Montana. TDD Nos. 1105-09 

and 1109-07. Dated August 20, 2012. [1,083 pages]

6. EPA-START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist, to file

regarding methodology used to create Reference 6 (Montana Fish, Wildlife & Parks (MFWP), 

Montana Fisheries Information System (MFISH), species search for Bull Trout within the Clark 

Fork River adjacent to the former Smurfit-Stone Mill. Dated March 22, 2013. [4 pages] 

7. Montana Department of Fish, Wildlife and Parks (MFWP). 2012. Montana Fisheries Information 

System (MFISH) Waterbody Report for Clark Fork River. Excerpt. Available at:

http://fwp.mt.gov/fishing/guide/waterbodyDetail.html?llid=1162072481455. Retrieved August 

29, 2012. [2 pages]

8. MFWP. 2012. Montana Fisheries Information System (MFISH) Waterbody Report regarding fish

distribution, fish population surveys, Bull Trout areas, angling days per year, protected areas, and 

Bull Trout fishing logs for the Clark Fork River from river mile 102.8 to 221.8. Available at: 

http://fwp.mt.gov/fishing/mFish/. Retrieved September, 2012. [15 pages] 

9. MFWP. 2009. Montana Statewide Angling Pressure (Mail Survey) 2009. Prepared by Robert C. 

McFarland and Jennifer Dykstra. Dated August 2010. Excerpt. A complete copy is available at:

http://fwp.mt.gov/fwpDoc.html?id=46247. Retrieved September, 2012. [25 pages] 

10. MFWP. 2009. Fisheries Division Job Progress Report. Statewide Fisheries Investigation. Survey 

and Inventory of Coldwater Rivers. Clark Fork River Creel Census: Rock Creek to Flathead 

River. Project No: F-78-R-2. Project Period: July 1, 1995 through June 30, 1996. [28 pages] 

11. MFWP. 2012. Electronic mail correspondence from David Schmetterling, Fisheries Biologist, 

Montana Fish, Wildlife and Parks, Missoula, MT to Jeff Miller, Senior Environmental Scientist, 
REFERENCES (Continued)

6 

Denver, CO regarding fish consumption and Bull Trout habitat on the Clark Fork River adjacent 

to and downstream of the Smurfit-Stone Mill. Dated September 11, 2012. [3 pages] 

12. MFWP. 2010. Montana’s Fishing Access Sites. Field Guide. Excerpt. Dated July 2010. A 

complete copy is available at: http://fwp.mt.gov/fwpDoc.html?id=45907. Retrieved September, 

2012. [5 pages]

13. U.S. Fish and Wildlife Service (USFWS). October 2002. Chapter 3, Clark Fork River Recovery 

Unit, Montana, Idaho, and Washington. Excerpt. U.S. Fish and Wildlife Service, Bull Trout 

(Salvelinus confluentus) Draft Recovery Plan. Portland, Oregon. A complete copy is available at:

http://www.fws.gov/pacific/bulltrout/RP/Chapter_3%20Clark%20Fork.pdf [23 pages] 

14. Montana Natural Heritage Program (MTNHP). 2012. Online Query for Montana Animal Species 

of Concern. Query filtered by fish species listed by the USFWS as endangered or threatened and 

present in Township 14N, Range 21 W. Available at:

http://mtnhp.org/SpeciesOfConcern/?AorP=a. Retrieved September 2012. [6 pages] 

15. MTNHP. 2012. Bull Trout – Salvelinus confluentus. Montana Field Guide. Montana Natural 

Heritage Program and Montana Fish, Wildlife and Parks. Available at:

http://FieldGuide.mt.gov/detail_AFCHA05020.aspx. Retrieved on September 4, 2012. [5 pages] 

16. Smurfit-Stone. Undated (circa 2000). Brochure entitled “Linerboard from the Missoula Mill”. [2 

pages] 

17. Montana Audubon Society. 2009. Brochure titled “Clark Fork River – Grass Valley, Important 

Bird Area”. Dated February 2009. [4 pages] 

18. Missoula County Rural Initiatives. 2010. Facts Related to Agriculture and Other Natural 

Resources Associated with the Smurfit-Stone Mill. Dated January 11, 2010. [1 page] 

19. Community Food and Agriculture Coalition (CFAC). 2010. Letter from CFAC to Missoula 

County Commissioners regarding Important Agricultural Land on Smurfit-Stone Property. Dated 

January 11, 2010. [1 page] 

20. MFWP. 2011. Letter from Mack Long, MFWP Regional Supervisor to Richard Opper, Director 

Montana Department of Environmental Quality regarding aquatic and wildlife concerns on the 

Smurfit-Stone Mill property. Dated March 9, 2011. [2 pages] 

21. Montana Department of Health and Environmental Sciences (MDHES). 1974. Environmental 

Impact Statement for the Proposed Expansion of the Hoerner-Waldorf Pulp and Paper Mill at 

Missoula, Montana (Final). Excerpt. Dated November 6, 1974. [57 pages] 

22. Smurfit-Stone Container Enterprises, Inc., Missoula Mill. 2004. Application for Renewal of 

Wastewater Discharge Permit No. MT-0000035. Excerpt. Dated November, 2004. [93 pages] 

23. Smurfit-Stone Container Enterprises, Inc. 2010. Montana Pollution Discharge Elimination 

System (MPDES) Permit application for MPDES Permit MT0000035. Approved by Barry Doner, 

General Manager, on January 21, 2010 and prepared by Jeff Briggs, Environmental Manager, 

Smurfit-Stone Container Enterprises, Inc. Excerpt. Dated December 22, 2009. [28 pages] 
REFERENCES (Continued)

7 

24. U.S. Geological Survey (USGS). 1999. Summary of Information on Synthetic Organic 

Compounds and Trace Elements in Tissue of Aquatic Biota, Clark Fork-Pend Oreille and 

Spokane River Basins, Montana, Idaho, and Washington, 1974-96. Water-Resources 

Investigations Report 98-4254. Excerpt. A complete copy is available at:

http://pubs.er.usgs.gov/publication/wri984254 Accessed January, 2013. [17 pages] 

25. EPA Technical Assistance Team (EPA-TAT-Zone II). 1993. Chemical Safety Audit. Stone 

Container Corporation. February 9-12, 1993. Dated August 16, 1993. [97 pages]

26. MDHES. 1985. Discharge Permit MT-0000035. Draft Environmental Impact Statement. 

Champion International Frenchtown Mill. Missoula County. Dated December 26, 1985. Excerpt.

[162 pages] 

27. MTNHP. 2012. Provisional Wetland and Riparian Area Mapping. Primrose Quadrangle.

Quadrangle Code: 4611482. Dated January 18, 2012. Available at:

http://mtnhp.org/nwi/maps.asp?LL=25 Accessed January, 2013. [2 pages, includes 1 map sheet] 

28. United States Bankruptcy Court for the District of Delaware. Undated (approximately January 

2010). Notice of Hearing to Consider Confirmation of the Joint Plan of Reorganization for 

Smurfit-Stone Container Corporation and its Debtor Subsidiaries and Plan of Compromise and 

Arrangement for Smurfit-Stone Container Canada Inc. and Affiliated Canadian Debtors. Excerpt. 

[1 page] 

29. Kim Briggerman. The Missoulian. 2011. Investment group buys Smurfit’s Frenchtown mill. May 

5, 2011. [3 pages] 

30. Forest Business Network. 2011. Green Investment Group Affiliate Acquires 3,200-Acre Paper 

Mill in Missoula, Montana. Dated May 9, 2011. Available at:

https://www.forestbusinessnetwork.com/2661/green-investment-group-affiliate-acquires-3200-

acre-paper-mill-in-missoula-montana/. Date Accessed: September 16, 2012. [2 pages]

31. Reference number reserved.

32. Barry Damschen Consulting, LLC. 2005. Solid Waste Class III Landfill License Application. 

Prepared for: Smurfit-Stone Container Enterprises, Inc. Dated November, 2005. Excerpt. [6

pages] 

33. Reference number reserved.

34. Reference number reserved.

35. MDEQ. 2000. Authorization to Discharge under the Montana Pollutant Discharge Elimination 

System. Permit No. MT0000035. [24 pages] 

36. MDHES. 1986. Champion International Frenchtown Mill. Discharge Permit MT-0000035. 

Addendum. Dated March 1986. Excerpt. [43 pages] 

37. EPA. 1998. 63 Federal Register No. 72. National Emission Standards for Hazardous Air 

Pollutants for Source Category: Pulp and Paper Production; Effluent Limitations Guidelines, 

Pretreatment Standards, and New Source Performance Standards: Pulp, Paper and Paperboard 

Category. Excerpt. Dated April 15, 1998. A complete copy is available at:
REFERENCES (Continued)

8 

http://www.epa.gov/osw/laws-regs/state/revision/frs/fr164-1.pdf. Accessed January, 2013. [5 

pages] 

38. MDHES. 1986. Champion International Frenchtown Mill. Discharge Permit MT-0000035. Final 

EIS. Dated August 1986. Excerpt. [38 pages] 

39. EPA. 1993. Water Quality Assessment of Proposed Effluent Guidelines for the Pulp, Paper and 

Paperboard Industry. Office of Science and Technology. Dated November 1993. Excerpt. [36 

pages] 

40. MFWP. 2012. Letter from Wm. Ladd Knotek, Fisheries Management Biologist, Montana Fish, 

Wildlife and Parks, regarding fishery and angler information for the Clark Fork River adjacent to 

and downstream of the former Smurfit-Stone Container Mill Site. Dated September 19, 2012. [1 

page] 

41. Opportunity Resources, Inc. 2012. Letter from Tim Furey, Director of Development, Opportunity 

Resources, Inc., to Peter Nielson, Missoula County regarding the catching and consumption of 

fish from the Clark Fork River. Dated September 14, 2012. Reference includes map of 

Opportunity Resources, Inc property located along the Clark Fork River approximately 2 miles 

downstream of Smurfit-Stone Mill Outfall 4. Map and property information from the Montana 

Cadastral Mapping Project, Montana State Library, available at http://svc.mt.gov/msl/mtcadastral. 

Accessed February 20, 2013. [2 pages]

42. Tetra Tech, Inc. 1998. MPDES Compliance Monitoring For Dioxins and Furans in Alluvial 

Sediment and Fish near the Stone Container Corporation Plant at Missoula, Montana. Dated 

January 9, 1998. Excerpt. [46 pages] 

43. Smith, L. N. 2006. Hydrogeologic Framework of the Lolo-Bitterroot Area, Mineral, Missoula, 

and Ravalli Counties, Montana. Montana Ground-Water Assessment Atlas 4, Part B, Map 2.

Open-File version July 2006. A copy is available at:

http://mbmggwic.mtech.edu/gwcpmaps/gwaa04map02untiled.pdf Accessed January, 2013. [1 

sheet] 

44. EPA. 2006. Final Report: Pulp, Paper, and Paperboard Detailed Study. EPA-821-R-06-016. 

Dated November 2006. Excerpt. A complete copy is available at:

http://water.epa.gov/lawsregs/lawsguidance/cwa/304m/upload/2006_12_27_guide_304m_2006_p

ulp-final.pdf Accessed January, 2013. [26 pages] 

45. EPA. 1990. USEPA/Paper Industry Cooperative Dioxin Study. “The 104 Mill Study”. Summary 

Report. Dated July 1990. [29 pages] 

46. Stone Container Corporation. 2004. Letter from Robert C. Boschee, Environmental Manager, 

Stone Container Corporation, to Bonnie Lovelace, DEQ, regarding company name change and 

intent to file application for a new discharge permit. Dated September 30, 2004. Excerpt. [3 

pages] 

47. MDEQ. 2011. Leaking Underground Storage Tank Query System report. Search criteria: Stone. 

Access on-line at: http://nris.mt.gov/deq/remsitequery/lust.aspx?qt=lust&name=stone. Retrieved 

on July 25, 2011. [1 page] 
REFERENCES (Continued)

9 

48. EPA-START. 2011. Preliminary Assessment. Smurfit-Stone Mill. Missoula, Missoula County, 

Montana. TDD No. 1105-06. Dated September 14, 2011. [77 pages] 

49. U.S. EPA. 1996. Using Qualified Data to Document an Observed Release and Observed 

Contamination. EPA540-F-94-028. OSWER 9285.7-14FS. Dated November 1996. [18 pages] 

50. Smurfit-Stone Container Enterprises, Inc. 2009. Missoula Mill Pond Statistics and Wastewater 

Treatment System Overview. Compiled by Terry McLaughlin, Smurfit-Stone Container 

Enterprises, Inc. Dated February 27, 2009. Reference includes electronic mail from Missoula 

City-County Health Department explaining origin of document. [3 pages] 

51. Stone Container Corporation. 1992. Letter and permit application from Laura Kosmalski, 

Environmental Engineer, for Stone Container’s existing landfills. Excerpt. Dated July 27, 1992. 

[90 pages] 

52. Peter Nielsen. 2012. Electronic mail from Joe Cummings, fishing outfitter on the Clark Fork 

River, to Peter Nielsen, Missoula City-County Health Department, regarding the keeping of 

finfish and crayfish at river access points near the Smurfit-Stone Mill. Dated September 21, 2012. 

[1 page] 

53. EPA-START. 2005. Quality Program Plans, Standard Operating Procedures. Volume 4: 

Technical Operating Procedures (TSOPs). Reference includes excerpts from TSOPs 4.16 (Surface 

and Shallow Depth Soil Sampling), 4.27 Basic Geoprobe® Operations, 4.11 Equipment 

Decontamination, 4.12 Ground water Sampling, 4.9 Monitor Well Installation, 4.17 Sediment 

Sampling, and 4.18 Surface Water Sampling. Excerpt. Dated September, 2005. [43 pages] 

54. Reference number reserved. 

55. Reference number reserved. 

56. Reference number reserved.

57. MDEQ. 2011. Complaint/Spill Report regarding dust emissions from the Smurfit-Stone Mill 

property. Dated October 5, 2011. [1 page] 

58. Grimestad, Dr. Garry. 1992. A Summary of Surface and Subsurface Hydrogeological Conditions 

Within and Near Stone Container Corporation’s Missoula Mill Landfill Area. Dated February 25, 

1992. [12 pages]

59. Hydrometrics, Inc. and Inskeep, Dr. William. 2004. Ground water Mixing Zone Investigation and 

Well Correlation Study, Stone Container Missoula Facility. Prepared for Stone Container 

Corporation. Dated November, 2004. [104 pages]

60. United States Geologic Survey (USGS). 2012. Mean annual flow rate for the Clark Fork River at 

gauging station # 12353000 from the years 1930 through 2011. Available at:

http://waterdata.usgs.gov/MT/nwis/current/?type=flow. Date accessed October 8, 2012. [4 pages]

61. EPA-START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist, EPASTART to Smurfit-Stone Mill HRS project file, regarding methodology and source data used in

searching for other industrial facilities near the Smurfit-Stone Mill, Missoula, Montana. 

Reference includes search results obtained from the EPA FRS and MDEQ CECRA databases, 
REFERENCES (Continued)

10 

available at: http://www.epa.gov/enviro/html/ and 

http://www.deq.mt.gov/StateSuperfund/default.mcpx , respectively. Dated March 22, 2013. [41 

pages] 

62. EPA-START. 2012. Memorandum from Jeff Miller, Senior Environmental Scientist, EPASTART to Robert Parker, Site Assessment Manager, EPA Region VIII regarding a suggested 

addendum to the Analytical Results Report for a Combined Site Inspection and Removal 

Assessment, Smurfit-Stone Mill, Near Missoula, Missoula County, Montana. Dated September 

26, 2012. [3 pages] 

63. Federal Emergency Management Agency (FEMA). 1988. Flood Insurance Rate Map, Missoula 

County, Montana and Incorporated Areas. Panel 1155E of 1900. Map Number 30063C1155E. 

Dated August 16, 1988. [2 pages, includes 1 map sheet] 

64. EPA. 2012. Clark Fork River Operable Unit of the Milltown Reservoir/Clark Fork River 

Superfund Site. Site Description and Map. Available at: 

http://www.epa.gov/Region8/superfund/mt/milltowncfr/. Dates accessed October 3, 2012 and 

October 9, 2012. [10 pages]

65. USGS. 2012. National Water Information System: Web Interface. Filtered manganese 

concentrations in the Clark Fork River at USGS Stations 12334550 (Clark Fork at Turah Bridge) 

and 12353000 (Clark Fork below Missoula). Available at:

http://nwis.waterdata.usgs.gov/usa/nwis/qwdata/ Accessed October 9, 2012. [20 pages]

66. Reference number reserved.

67. URS Operating Services (UOS). 2012. Data validation reports and data packages (from ALS 

Laboratory Group) for water dioxin analytical results. [288 pages] 

68. Reference number reserved.

69. Reference number reserved.

70. Andrew Wilcox. 2013. Memorandum from Dr. Andrew Wilcox, Geomorphologist, University of 

Montana, regarding a topographic survey conducted on the Clark Fork River immediately below 

its confluence with Albert Creek. Dated March 26, 2013. [6 pages] 

71. USGS. 1963. Primrose, Montana 7.5’ Series (Topographic) Quadrangle (N4652.5 – 

W11407.5/7.5). Photorevised 1978. [2 pages, includes 1 map sheet and one annotated close up of 

map sheet showing the Smurfit-Stone Mill area]

72. EPA-START. 2013. Memorandum from Nathan Williams, Geologist, EPA-START, regarding 

ground water elevations, flow direction within the surficial alluvial aquifer, and method used to 

generate a ground water contour figure included in the reference. Reference also includes ground 

water sampling field forms from the October EPA-START Combined SI and RA, and a cross 

sectional figure showing relation between ground water elevations in the surficial alluvial aquifer

and the Clark Fork River. Dated March 25, 2013. [19 pages]

73. EPA. 1992. National Study of Chemical Residues in Fish. Volume 1. EPA 823-R-92-008a. Dated 

September 1992. Excerpt. A complete copy is available at:

http://water.epa.gov/scitech/swguidance/fishshellfish/techguidance/library_index.cfm [25 pages] 
REFERENCES (Continued)

11 

74. U.S. FWS. 2010. Department of the Interior, Fish and Wildlife Service. Endangered and 

Threatened Wildlife and Plants: Post-Delisting Monitoring Plan for Bald Eagle (Haliaeetus 

leucocephalus). Federal Register Vol. 75, No. 107, Friday, June 4, 2010. Page 31811. [1 page]

75. Reference number reserved.

76. EPA-START. 2013. Signed Chains of Custody from the October 2011 Combined Site Inspection 

and Removal Assessment. Reference includes Sample Delivery Group Cover Sheets. [39 pages] 

77. EPA-START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist, EPASTART to Smurfit-Stone Mill site file regarding boring logs and monitoring well construction 

diagrams for Smurfit-Stone Mill site investigation. [14 pages] 

78. EPA-START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist, to SmurfitStone Mill HRS project file regarding sample quantitation limit calculations for Smurfit-Stone 

Mill results. Dated March 25, 2013. [65 pages] 

79. EPA-START. 2013. Memorandum from Jeff Miller, Senior Environmental Scientist, to SmurfitStone Mill HRS project file regarding Photographs from the October 2011 Combined Site 

Inspection and Removal Assessment, Smurfit-Stone Mill, Missoula, Montana. Reference includes 

10 photographs taken during the October 2011 Combined SI and RA. Dated March 25, 2013. [11 

pages]

80. EPA-START. 2013. Memorandum from Kent Alexander, Principal Chemist, to Smurfit-Stone 

Mill HRS project file regarding Direction of Bias of ‘J’-flagged 1,2,3,4,6,7,8-HpCDD analytical 

result for SSGW01 (background ground water sample). Dated March 26, 2013. [1 page]

81. Chemtech Consulting Group, Inc. 2011. Inventory sheets and IX-IN Forms (Method Detection 

Limits (Annually)) for inorganic analytes, for four U.S. Environmental Protection Agency 

Contract Laboratory Program Sample Delivery Group (SDG) files for SDGs: MH3BA0, 

MH3BA1, MH30T9, and MH30Z9. Dated January 11, 2011. Excerpt. [8 pages]

82. Computer Sciences Corporation. Electronic mail correspondence from Ryan Mroz, 

Environmental Coordinator – Regions 5 & 8, Computer Sciences Corporation, to Snehal Mehta, 

Chemtech Consulting Group, Inc. regarding new inorganic Contract Laboratory Program IDs to 

be assigned to samples within Case 41926. Reference contains spreadsheet included as 

attachment to electronic mail. Dated November 3, 2011. [3 pages].

Figures:

Figure 1: Facility Location Map

Figure 2: Property Details Map

Figure 3: Source and Observed Release Sample Location Map

Figure 4: Probable Points of Entry and Ground Water Segments from Sources 

Figure 5: Target Distance Limit Map
12 

SITE DESCRIPTION

The Smurfit-Stone Mill is an inactive integrated pulp and paper mill (i.e., integrated mills make pulp from 

wood or other raw materials, and then use this pulp to make paper) located in west-central Montana, 

approximately 12 miles northwest of the city of Missoula, in Missoula County. The street address of the 

property is 14377 Pulp Mill Road, Missoula, Montana (Ref. 3; Figure 1 of this HRS documentation 

record). More specifically, the geographical coordinates, as measured at sample SSSO0502, collected 

within Source No. 1 and south of the mill facility, are latitude 46.957781° north and longitude 

114.199623° west (Ref. 4; Figure 3 of this HRS documentation record). The EPA identification number, 

as recorded in the Comprehensive Environmental Response, Compensation, and Liability Information 

System (CERCLIS) database, is MTN000802850 (Ref. 3). 

The property, as defined by the outside perimeter of the land parcels that formerly constituted the mill 

property, covers approximately 3,150 acres (Ref. 4, pp. 1, 4; Figure 1 of this HRS documentation record). 

The core industrial footprint of the property includes the former mill, a wood chip staging area, the 

effluent clarifier, and the hog fuel area, and covers approximately 150 acres (Ref. 4, pp. 1, 4; Figure 2 of 

this HRS documentation record). Over 900 acres of the property consist of a series of unlined ponds used 

to store both treated (primarily through aeration) and untreated wastewater effluent from the mill, as well 

as primary sludge recovered from wastewater that entered the clarifier (Refs. 22, pp. 26, 27, 44; 48, p. 7; 

50; Figure 2 of this HRS documentation record). The presence and amount of standing water within each 

pond varies. Some of these ponds were subsequently used for landfilling various solid wastes produced at 

the mill (e.g., pond 19 became landfill ‘D’). Much of the remaining acreage of the property 

(approximately 1,800 acres) is currently used for agricultural purposes, with over 1,200 acres of 

grasslands for cattle grazing and over 600 acres irrigated for alfalfa and grain crops (Figure 2 of this HRS 

documentation record) (Refs. 18, p. 1; 19, p. 1).

While the core industrial part of the property is fenced and has a security building, other portions of the 

property are not fenced. In particular, access to the property is possible from the Clark Fork River, which 

forms its entire western boundary (Refs. 5, pp. 48, 51, 194; 48, pp. 55-57, 59, 71; Figures 1, 2 of this HRS 

documentation record).

The EPA is evaluating the Surface Water Migration Pathway for the Smurfit-Stone Mill. For HRS scoring 

purposes, the Smurfit-Stone Mill site consists of three source areas that have been documented, through 

chemical analysis, to contain hazardous substances. Source No. 1 comprises sludge ponds 3, 4, 5, and 17; 

Source No. 2 is the emergency spill pond 8; and Source No. 3 is wastewater storage pond 2 (Refs. 5, pp.

21-22, 31; 26, p. 6; 50, p. 2; Tables 1, 2 and 3 and Figure 3 of this HRS documentation record). Source 

No. 1 is considered as source type ‘pile’, while Sources No. 2, and No. 3 are considered to be source type

‘surface impoundment’ under the HRS (Ref. 1, pp. 51587, 51591). Additional potential sources of various 

hazardous substances at the property that have not been characterized to date include 11 additional 

wastewater storage ponds, 3 wastewater treatment aeration basins, 2 polishing ponds, a number of 

landfills, and the historical discharge of wastewater directly to the Clark Fork River via three outfalls

(Ref. 22, p. 44; Figure 2 of this HRS documentation record). 

The hazardous substances that have been detected in at least one of the sources listed above include, but 

are not limited to: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD); 1,2,3,7,8-Pentachlorodibenzo-pdioxin (1,2,3,7,8-PeCDD); 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin (1,2,3,6,7,8-HxCDD); 1,2,3,4,6,7,8-

Heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8-HpCDD); Total Tetrachlorodibenzo-p-dioxin (Total TCDD); 

2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF); 2,3,4,7,8-Pentachlorodibenzofuran (2,3,4,7,8-PeCDF); 

and the metals arsenic, cadmium, lead, and manganese (Ref. 5, p. 31, section 2.2.1 of this HRS 

documentation record for Sources 1, 2, and 3). 
13 

Some of these hazardous substances have been released into ground water beneath the property, as well as 

the Clark Fork River (located directly adjacent to the property), at concentrations elevated above 

background (Tables 4A and 4C of this HRS documentation record). 

The Clark Fork River is a fishery that supports a variety of finfish, including the federally designated 

threatened bull trout, as well as other species that are harvested for human consumption (Refs.10, pp. 7, 

20; 11, pp. 1, 2; 15, p. 1; 52). Significant areas of wetlands are present along the Clark Fork River, in 

areas adjacent to and downstream of the Smurfit-Stone Mill (Refs. 5, pp. 220-221; 27; Figures 1, 2 of this 

HRS documentation record). The segment of the Clark Fork River directly adjacent to the mill is listed as 

a Wildlife Protected Area by the Northwest Power and Conservation Council as it is a bald eagle nesting 

territory, a high-density bald eagle winter concentration area, a big game critical wintering/spring area, 

and a historical peregrine falcon nesting area (Ref. 8, p. 12). The mill property also lies within the Clark 

Fork River – Grass Valley Important Bird Area, so designated due to its significance to bird species of 

conservation concern (Ref. 17, pp. 1-4; Figures 1, 2 of this HRS documentation record). It is considered 

the largest and most significant wetland-water complex in the Missoula area for migratory species such as 

waterfowl, shorebirds, herons, and raptors (Ref. 20, p. 1). 
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16 

OPERATIONAL HISTORY

The Smurfit-Stone Mill began operation as a kraft pulp mill in the fall of 1957 (Refs. 16, p. 1; 26, p. 5; 

32, p. 1). The kraft process, a form of chemical pulping, has been a predominant method of fiber 

separation used in the U.S. paper industry, and was the method used at the Smurfit-Stone Mill (Ref. 25, p. 

11). Later expansions and improvements allowed the facility to produce paper, primarily rolls of kraft 

linerboard that were used in the production of corrugated containers (i.e., the outside layers of cardboard 

boxes). Linerboard produced at the mill was shipped to box plants where it was used to make a variety of 

corrugated containers (Ref. 16, p. 1). The mill used only softwoods (e.g., fir, larch, pine) in its process 

(Ref. 25, p. 10). The mill also produced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 

22, p. 7, 8; 25, p. 1; 26, p. 5). The mill filed for Chapter 11 bankruptcy in December 2009 and ceased 

operations in January 2010 (Refs. 28, p. 1; 30, p. 2). 

The following names have been associated with the ownership and/or operation of the mill throughout its 

operational history: Waldorf Paper Products Company, Waldorf-Hoerner, Hoerner Waldorf Corporation, 

Champion International Corporation, Stone Container Corporation, Smurfit-Stone Container Corporation, 

and Smurfit-Stone Container Enterprises Incorporated (Refs. 16, p. 1; 26, p. 5; 36, p. 5; 46, p. 1; 48, p. 8).

After operations ceased, the property was purchased by MLR Investments, and then M2Green 

Redevelopment, LLC (M2Green) (an affiliate of Green Investment Group) (Refs. 29; 30). M2Green is the 

current owner of the entire property (Ref. 30).

Wastewater

The Smurfit-Stone Mill used a large volume of water as a fiber carrier and solvent, generating vast 

amounts of wastewater (approximately 15 to 20 million gallons per day [mgd], or up to 6.99 billion 

gallons per year [e.g., 1994/1995]) (Refs. 21, pp. 13, 16, 21; 22, p. 26; 25, p. 40; 26, pp. 11, 14). A 

portion of this total was non-contact cooling water, the volume of which varied over the life of the mill 

(e.g., 1.0 mgd in 1974, to 5.0-6.5 mgd in 2004) (Refs. 21, p. 16; 22, p. 28).

During its initial operation, all wastewater was apparently released directly to the Clark Fork River 

without treatment (Refs. 26, p. 7; 38, p. 4). Following a fish kill in the summer of 1957, ponds were 

constructed and wastewater was temporarily stored onsite before being discharged to the river under high 

flow, spring runoff conditions (e.g., March through June) (Refs. 22, p. 5; 26, pp. 7, 11; 38, p. 4). Direct 

discharge of stored wastewater occurred to the Clark Fork River through one of three outfalls (Outfalls 1, 

2 and 3) (Refs. 22, pp. 3, 10, 27, 44; 26, p. 6). Non-contact cooling water was directed into a ditch that

discharged through a fourth outfall (Outfall 4) (Ref. 22, pp. 10, 44). It should be noted that two spills 

from the mill pulping area that entered the non-contact cooling water ditch were reported for 2001, but 

details of the spills, such as content and whether or not the spills reached the river, are not known (Ref. 

22, p. 30).

Seepage was one of the principal methods of discharge of wastewater from the mill since its inception 

(Ref. 22, p. 3). During the storage months, water seeped through the bottom of the storage ponds into the 

shallow, surficial alluvial aquifer (Ref. 22, pp. 3, 5; 26, p. 7, 11). By 1973, the major volume of 

wastewater, 10.56 mgd, was being disposed of by seepage to the shallow ground water, with another 5.28 

mgd being discharged directly into the Clark Fork during high river flow periods (Ref. 21, pp. 15, 16, 26, 

27). 

All seepage water that entered the shallow ground water in turn reached the river, as evidenced by 

increased color measurements taken on the river through times of low or no direct discharge, as well as by 

ground water flow measurements, which showed that the ground water flow direction was from the ponds 

to the river (Refs. 21, pp. 16, 26, 27, 38, 39; 22, pp. 14, 30; 26, pp. 11, 13, 94; 58, pp. 5, 6, 8, 9, 10, 11; 
17 

59, pp. 8, 16, 22, 40, 41, 51, 52, 77-86). By 1974, when an Environmental Impact Statement (EIS) for a 

proposed expansion of the mill was completed, ground water contamination of both the shallow, surficial 

alluvial aquifer and the deep aquifer beneath the mill property had been detected (Ref. 21, pp. 30, 31, 39).

A subsequent EIS for the mill, prepared because of a request for a discharge permit renewal, also 

mentions the plume of effluent-contaminated shallow ground water (Refs. 26, pp. 94, 97; 38, p. 9, 10, 14).

A 2004 report related to ground water beneath the mill property notes that the ground water beneath the 

ponds is generally similar in quality to the wastewater in the storage ponds (Ref. 59, p. 11).

Over the years, as the mill expanded and as the seepage rates from the ponds decreased due to 

accumulation of biological and residual organic solids in the bottom sediments of the ponds, additional 

storage ponds were constructed (Refs. 21, p. 15; 22, p. 5; 26, p. 11). By 1971, 15 ponds had been 

constructed covering approximately 750 acres (Refs. 21, p. 15; 26, p. 11). 

A primary clarifier was constructed in 1969/1970 to remove solid constituents (primarily unused pulp 

fiber and lime mud) from the wastewater, which was pumped into four sludge ponds (Refs. 21, p. 15; 22, 

pp. 5, 9, 26; 26, p. 12). A dredge had also been deployed in ponds to try to improve seepage into the 

ground water (Ref. 26, p. 12). 

In the 1970s, the mill experimented with ‘rapid-infiltration’ gravel basins as a means to facilitate seepage 

rates into ground water (Refs. 21, p. 28; 22, p. 5; 26, pp. 6, 12). The 1985 EIS (and its shortened ‘Final’ 

version completed in 1986) for the mill shows at least nine rapid infiltration basins scattered through the 

Smurfit-Stone property with a total area of approximately 120 acres (Refs. 26, pp. 6, 12; 38, p. 9). This 

process largely ended by 1983 due to clogging of the basins by organic matter (Refs. 22, p. 5; 26, pp. 12, 

14, 15). 

Secondary treatment, through the use of two aeration basins, also began at the mill in 1974 (Refs. 22, p. 5; 

26, p. 12). A third basin was added in 1990 (Ref. 22, p. 9). ‘Secondary’ sludge was generated from the 

biological treatment of water in the aeration basins and consisted of biological solids. Secondary sludge 

accumulated over time in the basins and was periodically removed by being pumped to the sludge ponds 

(Ref. 25, p. 50). 

From the aeration basins, wastewater flowed to polishing ponds, and then to the remaining storage ponds 

before discharge to the Clark Fork through one of the three outfalls (Refs. 21, pp. 15, 16; 22, pp. 27, 44; 

26, p. 6; 50). As storage ponds and the rapid-infiltrations basins became progressively plugged by 

organics, the mill became more reliant on the direct discharge of wastewater to the river (Refs. 22, p. 5; 

26, p. 7). In 1983, the mill applied for a permit that would allow it to directly discharge a portion of the 

wastewater into the river throughout the year, not solely during the high flows of spring (Refs. 22, p. 6; 

26, p. 7). A 2-year permit for this was granted by the Montana Department of Health and Environmental 

Sciences (MDHES, now the MDEQ) in 1984, allowing year-round discharge of treated wastewater to the 

Clark Fork River at any time when river flows exceeded 1,900 cfs (Refs. 22, p. 6). New permits with 

similar conditions allowing for year-round discharge were issued in December 1986 and September 2000 

(Refs. 22, p. 6; 35, pp. 1, 6). 

Beginning in 1997, a sludge dewatering facility processed the sludge to remove additional liquid 

(reducing volume being sent to the ponds) and to provide a fuel source for the multi-fuel boiler (Ref. 22, 

p. 10).
18 

Hazardous Substances in Wastewater, Sludge and Pulp

Pollutants of concern in pulp and paper mill effluent include acetone, ketones, catechols, guaiacols, 

aldehydes, chloroform, methylene chloride, chlorinated phenols, polychlorinated dibenzo-p-dioxins 

(PCDDs) (dioxins) and polychlorinated dibenzofurans (PCDFs) (furans), metals, and polycyclic aromatic 

compounds (PACs) (Refs. 39, p. 13; 44, pp. 1-1, 1-5). The EPA has found that three groups of pollutants 

drive the toxic and nonconventional pollutant loadings for the Pulp and Paper industry: dioxin and dioxinlike compounds, PACs, and metals (Ref. 44, pp. 3-1, 3-2, 3-3, 3-4, 3-10, 4-7, 5-1). 

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 

4, 5; 44, p. 1-5; 45, p. 3). In 1990, the EPA published a report summarizing analytical results from the 

sampling of 104 pulp and paper mills across the U.S. that practiced chlorine bleaching of chemically

produced pulps (Ref. 45, p. 3). Samples were collected from three ‘export matrices’: bleached pulp, 

wastewater sludge, and wastewater effluent (Ref. 45, p. 3). The results of chemical analysis of the 

samples showed that, for kraft mills with bleaching operations, 2,3,7,8-TCDD was detected in 90 percent

of overall samples, and 2,3,7,8-TCDF was detected in 97 percent of overall samples (Ref. 45, p. 4). 

Specifically for wastewater effluent samples from bleaching kraft mills, 90 of 107 samples (84 percent) 

contained detectable amounts of 2,3,7,8-TCDD, and 104 of 111 samples (94 percent) contained detectable 

quantities of 2,3,7,8-TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent ) 

collected from bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of 

the 97 samples contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 7, 8). Pulp samples yielded 

similar results, with 98 of 104 (94 percent) samples of bleached kraft softwood pulp showing detectable 

levels of 2,3,7,8,-TCDD, and 99 of 102 (97 percent) samples showing detectable levels of 2,3,7,8-TCDF 

(Ref. 45, p. 5). 

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine 

mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted 

CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8-

PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27). 

The Smurfit-Stone mill produced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 21, 

pp. 7, 13, 16; 22, pp. 7, 9; 25, p. 9; 26, p. 5). For example, the mill produced an average of 159 tons of 

bleached product in 1973 (Ref. 21, pp. 7, 13). For this year, the mill reported that 30,000 gallons of water 

were needed per ton of bleached product; therefore, the wastewater discharge from the bleach plant was 

computed to average 4.8 million gallons per day (Ref. 21, p. 13).

Analytical results from the sampling of four sludge ponds, an emergency spill pond, and a wastewater 

storage pond on the Smurfit-Stone Mill property show that a number of dioxin and furan compounds are 

present in the ponds (Ref. 5, pp. 67, 69, 72-73, 403-404, 416-418; Tables 1, 2 and 3 of this HRS 

documentation record).

Sources of metals in kraft pulp and paper mill waste streams include wood (calcium, potassium, 

manganese), spent pulping solutions that dissolve metals from wood, papermaking additives such as alum 

and kaolin clay, soils on logs and wood chips, green liquor dregs (particularly for manganese), and makeup lime used in the causticizing reaction (Ref. 44, pp. 6-20, 6-22, 6-23). 

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by 

pulp and paper mills through the Toxics Release Inventory (TRI) database (Ref. 44, pp. xvi, 1-1, 4-8). 

Manganese was the metal with the highest toxic-weighted pound equivalents (TWPE) reported for both 
19 

types of mills (Ref. 44, p. 4-8). Additionally, wood is noted to be a major source of manganese in the 

kraft process (Ref. 44, p. 6-20). The Smurfit-Stone Mill (known at that time as Stone Container 

Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6). 

At the Smurfit-Stone Mill, the dregs from the recausticizing operation and fly ash from the multi-fuel 

boiler were both disposed of into the sludge ponds (Ref. 22, pp. 8, 9). After passing through the clarifier 

and/or sludge ponds, wastewater discharge from all portions of the paper and pulp mill, including from 

the recausticizing plant, was sent to the aeration basins and then the wastewater storage ponds (Ref. 22, 

pp. 26, 27). These discharges could also bypass the clarifier and report directly to the emergency spill 

pond 8 (Ref. 22, p. 26). The presence of metals in wastewater discharge from the mill was noted in the 

EIS for the mill, and total manganese was detected at a concentration of 0.219 milligrams per liter (mg/L) 

within a representative wastewater sample collected by the Smurfit-Stone Mill as part of MPDES permit 

requirements (Refs. 22, pp. 56, 61, 81). 

Analytical results from the sampling of four sludge ponds, an emergency spill pond, and a wastewater 

storage pond on the Smurfit-Stone Mill property show that a number of metals, including arsenic, 

cadmium, manganese, and lead are present in the ponds (Ref. 5, pp. 67, 69, 72-73, 1006-1011, 1036-

1050; Tables 1, 2 and 3 of this HRS documentation record). 

PREVIOUS INVESTIGATIONS

Most environmental investigations conducted at the Smurfit-Stone Mill appear to have been limited to 

those undertaken by the mill or by the MDHES in relation to the MPDES permitting process (including 

environmental compliance monitoring performed by the mill) (Refs. 22, p. 6; 26, pp. 7, 16, 20-21; 36, p. 

14, 15, 17; 42, p. 3). A few of these investigations will be discussed in more detail in later sections of this 

HRS documentation record. 

Site assessments have apparently been performed at six of eight petroleum storage tank locations at the 

Smurfit-Stone Mill. The assessments found evidence of releases at all six locations. The remediation of at 

least two of these releases is currently being overseen by the Petroleum Release Section of the MDEQ

(Ref. 47). 

Investigations performed by the EPA prior to 2011 appear to be limited to a chemical safety audit 

conducted by the Region 8 Technical Assistance Team from February 9 through 12, 1993. The purpose of 

the audit was to document facility processes, chemical hazards, accidental release prevention practices, 

and emergency response preparedness and planning (Ref. 25, pp. 18, 19).

In 2011, URS Operating Services (UOS), on behalf of the EPA Superfund Technical Assessment and 

Response Team (EPA-START) program, was tasked with conducting a Preliminary Assessment of the 

Smurfit-Stone Mill property (Ref. 48, p. 6). During this assessment, EPA-START identified numerous 

potential sources of contamination at the property, including sludge ponds, aeration basins and treated 

water ponds, an emergency spill pond, landfills and other dumping locations, various process areas within 

the industrial footprint, a former landfarming area, and ASTs and USTs (Ref. 48, pp. 13-15, 19-25, 33, 

52-72). The assessment also identified targets potentially at risk from contaminant migration, including 

surface water users (e.g., fisherman), wetlands, game fish populations, and ground water users (Ref. 48, 

pp. 27-34).

In October 2011, EPA-START conducted a combined site inspection and removal assessment at the 

Smurfit-Stone Mill property (Ref. 5, p. 7). Field activities included the collection of soil/source, surface 

water, sediment, and ground water samples (collected from existing monitoring and domestic wells, as 

well as newly installed monitoring wells) (Refs. 5, pp. 7, 20-23, 67-68, 72-78, 200-212; 72, pp. 3-17). The 
20 

source/soil and ground water samples collected from the surficial alluvial aquifer beneath the property

contained dioxins and furans, and metals (Ref. 5, pp. 30-34, 60, 69, 71; Tables 1, 2, 3, and 4C of this HRS 

documentation record). Sediment samples collected from the Clark Fork River were also noted to contain 

dioxins and furans above background levels, while surface water samples from the Clark Fork River 

contained dissolved manganese above background levels (Ref. 5, pp. 34, 35, 68, 73-74, 199, 210-211, 

397; Ref. 78, p. 21; Tables 4A and 4B of this HRS documentation record). 
21 

SOURCE DESCRIPTION

2.2 SOURCE CHARACTERIZATION

2.2.1 Source Identification

Number of source: Source No. 1 

Name of source: Sludge ponds 3, 4, 5, 17

Source Type: Pile

Location of Source (with reference to a map of the site): The four sludge ponds (piles) that constitute

Source No. 1 are located in the south-central portion of the Smurfit-Stone Mill property, to the west and 

southwest of the industrial core area, as can be seen in Figure 2 of this HRS documentation record.

For HRS scoring purposes, these four piles will be aggregated and considered one source, as they were 

utilized by the mill for the same purpose, have identical containment characteristics, contain similar 

contaminants, and are located adjacent to each other. Since the closing of the mill, sludge pond 3 has been 

covered with a layer of wood chips, but this covering layer is not complete and water is able to penetrate 

this covering material (Refs. 5, pp. 37, 48, 189, 202; 48, p. 61; 79, p. 10).

As a result of (and to prevent additional) accumulation of sludge in the wastewater storage ponds, a 

primary clarifier was constructed at the Smurfit-Stone Mill in 1969-1970 (Ref. 22, p. 5). The clarifier 

removed solid constituents (primarily unusable wood pulp fibers from the pulp and papermaking process 

and calcium carbonate from the recausticizing operation) from the mill wastewater (Ref. 22, pp. 8, 9). Fly 

ash (aka hog fuel ash) and unburned green liquor dregs (unburned carbon from the recovery boilers) was 

also a component of sludge, or was pumped into the sludge ponds (Refs. 22, pp. 4, 8, 9). In addition to 

process wastewater flows from the pulp mill, paper mill, and recausticizing plant, the primary clarifier 

also received excess white water and stock tank overflow (excess water derived from the drying of paper), 

as well as wastewater from the power and recovery area, the old corrugated cardboard (OCC) plant and 

the bleach plant (Refs. 21, p. 16; 22, pp. 4, 26; 25, pp. 15, 48, 50). A component of this wastewater would 

have been incorporated into the sludge. 

This sludge was pumped from the clarifier into four sludge ponds numbered 3, 4, 5, and 17 (Refs. 21, pp. 

15, 16; 22, pp. 5, 9, 25; 50). Ponds 3, 4 and 5 were originally wastewater storage ponds and, therefore, 

would not have been lined, as the disposal of a majority of liquid effluent was into the ground water 

system via percolation through pond bottoms (Refs. 21, pp. 15, 16, 26, 27; 22, p. 3; 26, p. 6; 38, p. 5).

Sludge pond 17 was constructed at some point after 1974 (it is not shown on a map of the facility within a 

report dated 1974) (Ref. 21, p. 17). During the combined SI and RA in October 2011, soil bores were 

placed into all four of these sludge ponds to depths where native in situ material was encountered beneath 

the sludge. No liner was encountered in any of these borings (Ref. 77, pp. 2, 3, 5, 10-13). In 1992, it was 

estimated that 54 tons of sludge were generated each day (Ref. 51, p. 11). Prior to the operation of the 

clarifier, wastewater containing sludge was temporarily held in wastewater storage ponds (as well as 

directly discharged to the Clark Fork River) (Ref. 22, p. 5).

During the time of both the PA in June 2011 and the combined SI and RA in October 2011, all four ponds 

were mostly dry but had areas of standing water (Refs. 5, pp. 47, 48, 185, 186, 189, 190; 48, p. 53, 54, 61-

63). No evidence of a liner or functioning leachate collection and removal system above a liner was 

observed at any of the four ponds (Ref. 77, pp. 2, 3, 5, 10-13). None of the four ponds had a maintained 

engineered cover (Refs. 5, pp. 48, 185, 186, 189, 190; 48, pp. 53, 54, 61-63; 79, p. 4). The four surface 
22 

piles have a combined surface area of 91 acres, and combined volume of 899 acre-feet or approximately 

1,450,087 cubic yards (yd3

) (Ref. 50).

In October 2011, EPA-START conducted a combined site inspection and removal assessment at the 

Smurfit-Stone Mill (Ref. 5, p. 7). Field activities included the collection of 14 samples from directly 

within the four sludge ponds (Ref. 5, pp. 20, 21, 72, 73; Figure 3 of this HRS documentation record).

Eight of these samples were collected from 0 to 2 feet below ground surface (bgs) and six of these 

samples were collected from below 2 feet bgs (Ref. 5, pp. 21, 72, 73). Samples collected from the sludge 

ponds were generally moist, organic-rich, dark grey to black, and non-cohesive, and most had a strong 

sulfur odor. Most samples were also noticeably fibrous. Occasional grey layers of ash and lime were also 

observed (Refs. 5, p. 212; 77, pp. 2, 3, 5, 10-13). 

All 14 samples are used to characterize Source No. 1 (Ref. 5, pp. 20, 21, 72, 73). These samples contained 

hazardous substances, including: 2,3,7,8-TCDD; 1,2,3,7,8-PeCDD; 1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8-

HpCDD; Total-TCDD; 2,3,7,8-TCDF; 2,3,4,7,8-PeCDF; arsenic; cadmium; lead; and manganese (Ref. 5, 

pp. 30-32, 60, 67, 69, 72, 403-404, 416-418, 1006-1011, 1038-1045; Table 1 of this HRS documentation 

record).

2.2.2 Hazardous Substances

EPA-START collected the source samples listed in Table 1 during the October 2011 combined site 

inspection and removal assessment at the Smurfit-Stone Mill property (Ref. 5, p. 7). Fourteen samples 

were collected from Source No. 1 during the sampling event (Ref. 5, pp. 21, 72, 73; Figure 3 of this HRS 

documentation record). Eight of these samples were collected from 0 to 2 feet bgs and six of these 

samples were collected from below 2 feet bgs (Ref. 5, pp. 20, 21, 72, 73). All 14 samples will be used to 

characterize Source No. 1 (Ref. 5, pp. 20-21, 72, 73).

All of the samples for Source No. 1 were collected during the same sampling event and in accordance 

with the same sampling procedures, which are described in the EPA-START Quality Program Plans, 

Standard Operating Procedures, Volume 4: Technical Standard Operating Procedures (TSOPs) 4.16 

“Surface and Shallow Depth Soil Sampling” and 4.27 “Basic Geoprobe® Operations” (Ref. 53, pp. 7-18).

All Source No. 1 samples were collected with disposable plastic scoops either from a plastic core sleeve 

emplaced into the source material with a hydraulic-push machine or, in places that the machine could not 

safely access, directly from the surface of the source being sampled (Ref. 5, pp. 21, 25, 186, 189). All 

plastic sleeves and scoops used during the project were new, certified clean, single-use disposable sleeves 

and scoops that were used once (Ref. 5, pp. 25, 57, 202-205, 210). 

A steel shovel was used at some locations to break up the surface material (e.g., if it was frozen) to ease 

the collection of the samples with plastic scoops (Ref. 5, p. 25). The shovel was decontaminated prior to 

its initial use and then between sampling locations where it was used as per EPA-START TSOP 4.11 

“Equipment Decontamination” (Ref. 53, pp. 13, 14). A rinsate blank was collected from the shovel to 

document thoroughness of the decontamination procedures and to determine if any cross-contamination 

occurred (Ref. 5, pp. 25, 54, 78, 187). Results from the rinsate sample show that cross-contamination did 

not occur (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134). 

For the deeper locations where a hydraulic-push machine was used to first collect source material into a 

plastic sleeve, the same stainless steel cutting shoe was used for each location. The cutting shoe is the 

only reusable part of the sampling system that makes contact with in situ soils. The drilling subcontractor 

decontaminated the cutting shoe prior to its initial use and then between sampling locations using a 

method equivalent to that in TSOP 4.11. A rinsate blank (sample SSSW89) was collected from both the 
23 

shovel and the cutting shoe to assess the quality and thoroughness of the decontaminating procedures 

used (Ref. 5, pp. 25, 54, 78, 187). The analytical results from this rinsate sample showed no 

concentrations of contaminants of concern (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134) 

All samples from Source No. 1 were analyzed for dioxins and furans using EPA Method 8290A by the 

private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for total target analyte list 

(TAL) metals using ICP-AES using method CLP-ISM01.3 by the EPA CLP RAS laboratory, Chemtech 

Consulting Group, Inc., in Mountainside, New Jersey. EPA-START contractor TechLaw, Inc. reviewed 

all dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-pdioxins (CDDs) and Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all 

metals data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for 

Inorganic Data Review,” January 2010 (Ref. 5, pp. 7-9, 52, 53, 394-395, 397, 408, 410, 989-990, 992, 

1022, 1024). 

Sample-specific quantitation limits have been calculated for each Source No. 1 analytical result and are 

listed in Table 1 of this HRS documentation record (Refs. 1, p. 51586; 78, pp. 3-9, 11-13, 40-65). 

Logbook notes regarding sample collection details, including sample collection dates, are provided in 

Reference 5 (pp. 195-215). The chain-of-custody records are provided in Reference 76 (pp. 1-39) and 

Reference 67 (pp. 148-149, 153). The locations of all samples are depicted in Figure 3 of this HRS 

documentation record, and are described in Reference 5 (pp. 72, 73).

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 

4, 5; 44, pp. 1-5; 45, pp. 3). The Smurfit-Stone mill produced bleached pulp and paper from 1960 through 

1999 (Refs. 16, p. 1; 21, pp. 7, 13, 16; 22, pp. 7, 9; 25, p. 9; 26, p. 5). Sludges recovered from wastewater 

clarifying of bleached pulp typically contain dioxins and furans (Refs. 25, p. 50; 45, pp. 3, 5, 6, 14, 15, 

22, 24, 26). In one EPA study where sludge from 104 bleaching pulp and paper mills was sampled and 

analyzed, 94 of 97 sludge samples (97 percent) collected from bleaching kraft mills contained detectable 

amounts of 2,3,7,8-TCDD, and 100 percent of the 97 samples contained detectable amounts of 2,3,7,8-

TCDF (Ref. 45, pp. 5, 8). 

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine 

mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted 

CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8-

PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27). 

Analytical results from the sampling of four sludge ponds on the Smurfit-Stone Mill property show that a 

number of dioxin and furan compounds are present in the ponds (Refs. 5, pp. 67, 69, 72-73, 403-404, 416-

418; Table 1 of this HRS documentation record).

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by 

pulp and paper mills through the TRI database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with 

the highest TWPE reported for both types of mills (Ref. 44, p. 4-8). Additionally, wood has been 

identified as a major source of manganese in the kraft process (Ref. 44, p. 6-20). The Smurfit-Stone Mill 

(known at that time as Stone Container Corporation) was one of the mills for which TRI data was 

compiled (Ref. 44, p. A-6). 

The presence of metals in wastewater discharge from the mill was noted in the EIS for the mill, and total 

manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample 

collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Refs. 22, pp. 56, 61, 81). 
24 

Analytical results from the sampling of four sludge ponds on the Smurfit-Stone Mill property show that a 

number of metals including arsenic, cadmium, manganese and lead are present in the ponds (Ref. 5, pp. 

67, 69, 72-73, 1006-1011, 1038-1045; Table 1 of this HRS documentation record). 
25 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

SSSO0502 10/25/11 sludge 

pond 17

2,3,7,8-TCDD 4.72 0.14 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 40

“ “ “ 1,2,3,7,8-PeCDD 13.4 0.19 5, pp. 67, 72, 212, 403; 67, p. 

153;78, p. 41

“ “ “ 1,2,3,6,7,8-HxCDD 11.4 0.26 5, pp. 67, 72, 212, 403; 67, p. 153;

78, p. 41 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

48.5 0.31 5, pp. 67, 72, 212, 403; 67, p. 153;

78, p. 41 

“ “ “ Total-TCDD 278 0.14 5, pp. 67, 72, 212, 403; 67, p. 153;

78, p. 42

“ “ “ 2,3,7,8-TCDF 34.4 0.69 5, pp. 67, 72, 212, 403; 67, p. 153;

78, p. 42

“ “ “ 2,3,4,7,8-PeCDF 29.7 0.18 5, pp. 67, 72, 212, 403; 67, p. 153;

78, p. 42

(MH30Q4) “ “ Arsenic 10.7 0.30 5, pp. 67, 72, 212, 1006, 1065; 76, 

p. 29; 78, p. 3 

“ “ “ Lead 23.3 0.16 5, pp. 67, 72, 212, 1006, 1065; 76, 

p. 29; 78, p. 3 

“ “ “ Manganese 1,590 0.05 5, pp. 67, 72, 212, 1006, 1065; 76, 

p. 29; 78, p. 4

SSSO0514 10/27/11 “ 2,3,7,8-TCDD 0.823 0.58 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 49 

“ “ “ 1,2,3,6,7,8-HxCDD 8.89 1.75 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 50

“ “ “ 1,2,3,4,6,7,8-

HpCDD

24.6 2.92 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 50 
26 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

“ “ “ Total-TCDD 1.93 0.58 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 50

“ “ “ 2,3,7,8-TCDF 6.23 0.98 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 51

(MH3BB7) “ “ Manganese 870 0.19 5, p. pp. 67, 72, 203, 1038; 76, pp. 

28, 30; 78, p. 9; 82, p. 3 

SSSO0602 10/25/11 “ 2,3,7,8-TCDD 22.4 1.02 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 43 

“ “ “ 1,2,3,7,8-PeCDD 73.4 0.68 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 43

“ “ “ 1,2,3,6,7,8-HxCDD 67.7 0.83 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 43

“ “ “ 1,2,3,4,6,7,8-

HpCDD

311 1.64 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 44

“ “ “ Total-TCDD 2,320 1.02 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 44 

“ “ “ 2,3,7,8-TCDF 164 2.49 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 44 

“ “ “ 2,3,4,7,8-PeCDF 148 0.98 5, pp. 67, 72, 212, 403; 67, p. 153; 

78, p. 45

(MH30Q6) “ “ Arsenic 26.9 0.41 5, pp. 67, 72, 212, 1007, 1065; 76, 

p. 29; 78, p. 4

“ “ “ Cadmium 12.5 0.02 5, pp. 67, 72, 212, 1007, 1065; 76, 

p. 29; 78, p. 4

“ “ “ Lead 61.4 0.21 5, pp. 67, 72, 212, 1007, 1065; 76, 

p. 29; 78, p. 5 
27 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

“ “ “ Manganese 4,020 0.06 5, pp. 67, 72, 212, 1007, 1065; 

76, p. 29; 78, p. 5

SSSO0612 10/27/11 “ 1,2,3,6,7,8-HxCDD 6.5 2.60 5, pp. 67, 72, 203, 416; 67, p. 148;

78, p. 51

“ “ “ 1,2,3,4,6,7,8-

HpCDD

31.0 3.51 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 52 

“ “ “ Total-TCDD 2.28 1.90 5, pp. 67, 72, 203, 416; 67, p. 148; 

78, p. 52 

(MH3BB8) “ “ Manganese 1,220 0.21 5, pp. 67, 72, 203, 1039; 76, p. 30;

78, p. 9; 82, p. 3

SSSO0702 10/26/11 sludge 

pond 3

2,3,7,8-TCDD 34.3 1.31 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 45

“ “ “ 1,2,3,7,8-PeCDD 92.7 1.78 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 45

“ “ “ 1,2,3,6,7,8-HxCDD 78.1 2.08 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 46 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

299 3.36 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 46 

“ “ “ Total-TCDD 1,450 1.31 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 46

“ “ “ 2,3,7,8-TCDF 317 6.38 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 47

“ “ “ 2,3,4,7,8-PeCDF 237 3.36 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 47

(MH30Q8) “ “ Arsenic 71.4 0.19 5, pp. 67, 72, 202, 1008, 1065; 76, 

p. 29; 78, p. 5 
28 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

“ “ “ Cadmium 17.9 0.01 5, pp. 67, 72, 202, 1008, 1065; 78, 

p. 6

“ “ “ Lead 108 0.10 5, pp. 67, 72, 202, 1008, 1065; 76, 

p. 29; 78, p. 6

“ “ “ Manganese 6,840 0.03 5, pp. 67, 72, 202, 1008, 1065; 76, 

p. 29; 78, p. 6 

SSSO0716 10/26/11 “ 2,3,7,8-TCDD 11.8 0.99 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 53 

“ “ “ 1,2,3,6,7,8-HxCDD 11.5 1.79 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 53

“ “ “ 1,2,3,4,6,7,8-

HpCDD

81.7 2.83 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 53

“ “ “ Total-TCDD 11.8 0.99 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 54

“ “ “ 2,3,7,8-TCDF 25.7 1.67 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 54 

“ “ “ 2,3,4,7,8-PeCDF 1.70 0.92 5, pp. 67, 72, 202, 404; 67, p. 

153; 78, p. 54 

(MH30Q9) “ “ Lead 7.9 0.17 5, pp. 67, 72, 202, 1009, 1065; 76, 

p. 29; 78, p. 7

“ “ “ Manganese 89.7 0.05 5, pp. 67, 72, 202, 1009, 1065; 76, 

p. 29; 78, p. 7

SSSO0802 10/26/11 “ 1,2,3,7,8-PeCDD 5.51 0.71 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 47

“ “ “ 1,2,3,6,7,8-HxCDD 95.5 1.61 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 48 
29 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

54.4 1.32 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 48

“ “ “ Total-TCDD 39.4 0.68 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 48

“ “ “ 2,3,7,8-TCDF 19.7 0.76 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 49 

“ “ “ 2,3,4,7,8-PeCDF 6.25 0.34 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 49 

(MH30R0) “ “ Lead 18.5 0.37 5, pp. 67, 72, 203, 1010, 1065; 76, 

p. 29; 78, p. 7

“ “ “ Manganese 2,090 0.11 5, pp. 67, 72, 203, 1010, 1065; 76, 

p. 29; 78, p. 7

SSSO0816 10/26/11 “ 2,3,7,8-TCDD 11.6 2.96 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 55

“ “ “ 1,2,3,6,7,8-HxCDD 24.9 6.21 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 55 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

148 8.28 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 55 

“ “ “ Total-TCDD 11.6 2.96 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 56

“ “ “ 2,3,7,8-TCDF 33.8 9.17 5, pp. 67, 72, 203, 404; 67, p. 

153; 78, p. 56

(MH30R1) “ “ Lead 7.2 0.31 5, pp. 67, 72, 203, 1011, 1065; 76, 

p. 29; 78, p. 8

“ “ “ Manganese 514 0.09 5, pp. 67, 72, 203, 1011, 1065; 76, 

p. 29; 78, p. 8 
30 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

SSSO1102 10/27/11 sludge 

pond 4

2,3,7,8-TCDD 1.50 1.40 5, pp. 67, 73, 204, 417; 67, p. 148; 

78, p. 57

“ “ “ 1,2,3,6,7,8-HxCDD 5.58 4.01 5, pp. 67, 73, 204, 417; 67, p. 

148; 78, p. 57

“ “ “ 1,2,3,4,6,7,8-

HpCDD

58.0 5.16 5, pp. 67, 73, 204, 417; 67, p. 148; 

78, p. 57 

“ “ “ Total-TCDD 3.87 1.40 5, pp. 67, 73, 204, 417; 67, p. 148; 

78, p. 58 

“ “ “ 2,3,7,8-TCDF 9.51 1.63 5, pp. 67, 73, 204, 417; 67, p. 148; 

78, p. 58

(MH3BC2) “ “ Cadmium 12.7 0.04 5, pp. 67, 73, 204, 1043; 76, p. 30;

78, p. 9; 82, p. 3

“ “ “ Manganese 797 0.15 5, pp. 67, 73, 204, 1043; 76, p. 30; 

78, p. 10; 82, p. 3

SSSO1110 10/27/11 “ 2,3,7,8-TCDD 13.6 0.46 5, pp. 67, 73, 417; 67, p. 148; 77, 

p. 13; 78, p. 58 

“ “ “ 1,2,3,6,7,8-HxCDD 15.8 1.14 5, pp. 67, 73, 417; 67, p. 148; 77, 

p. 13; 78, p. 59 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

115 2.48 5, pp. 67, 73, 417; 67, p. 148; 77, 

p. 13; 78, p. 59

“ “ “ Total-TCDD 15.7 0.46 5, pp. 67, 73, 417; 67, p. 148; 77, 

p. 13; 78, p. 59

“ “ “ 2,3,7,8-TCDF 41.3 2.28 5, pp. 67, 73, 417; 67, p. 148; 77, 

p. 13; 78, p. 60

“ “ “ 2,3,4,7,8-PeCDF 1.90 1.04 5, pp. 67, 73, 417; 67, p. 148; 77, 

p. 13; 78, p. 60 
31 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

(MH3BC3) “ “ Manganese 1,180 0.07 5, pp. 67, 73, 1044; 76, p. 30; 77, 

p. 13; 78, p. 11; 82, p. 3

SSSO1202 10/27/11 “ 1,2,3,4,6,7,8-

HpCDD

52.9 4.37 5, pp. 67, 73, 204, 418; 67, p. 149; 

78, p. 61

“ “ “ Total-TCDD 4.59 1.31 5, pp. 67, 73, 204, 418; 67, p. 149; 

78, p. 61 

“ “ “ 2,3,7,8-TCDF 3.91 1.01 5, pp. 67, 73, 204, 418; 67, p. 149; 

78, p. 61 

(MH3BC4) “ “ Cadmium 12.1 0.02 5, pp. 67, 73, 204, 1045; 76, p. 23; 

78, p. 13; 82, p. 3

“ “ “ Manganese 1,990 0.07 5, pp. 67, 73, 204, 1045; 76, p. 23; 

78, p. 13; 82, p. 3

SSSO0902 10/27/11 sludge 

pond 5 

1,2,3,6,7,8-HxCDD 0.756 0.24 5, pp. 67, 72, 204, 416; 67, p. 148; 

78, p. 62

“ “ “ 1,2,3,4,6,7,8-

HpCDD

9.61 0.74 5, pp. 67, 72, 204, 416; 67, p. 148; 

78, p. 62 

“ “ “ Total-TCDD 2.17 0.09 5, pp. 67, 72, 204, 416; 67, p. 148; 

78, p. 62 

“ “ “ 2,3,7,8-TCDF 0.992 0.10 5, pp. 67, 72, 204, 416; 67, p. 148; 

78, p. 63

(MH3BB9) “ “ Manganese 598 0.05 5 pp. 67, 72, 204, 1040; 76, p. 23; 

78, p. 11; 82, p. 3

SSSO0916 10/27/11 “ 1,2,3,6,7,8-HxCDD 7.03 4.01 5, pp. 67, 72, 204, 417; 67, p. 148; 

78, p. 63

“ “ “ 1,2,3,4,6,7,8-

HpCDD

46.7 4.28 5, pp. 67, 72, 204, 417; 67, p. 148; 

78, p. 63 
32 

TABLE 1: Source Samples - Source No. 1 (Sludge Ponds) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

“ “ “ 2,3,7,8-TCDF 18.7 1.60 5, pp. 67, 72, 204, 417; 67, p. 148; 

78, p. 64

“ “ “ 2,3,4,7,8-PeCDF 79.2 1.26 5, pp. 67, 72, 204, 417; 67, p. 148; 

78, p. 64

(MH3BC0) “ “ Manganese 717 0.07 5, pp. 67, 72, 204, 1041; 76, p. 23;

78, p. 12; 82, p. 3 

SSSO1002 10/27/11 “ 2,3,7,8-TCDF 3.25 1.79 5, pp. 67, 72, 204, 417; 67, p. 148; 

78, p. 65 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

31.4 6.55 5, pp. 67, 72, 204, 417; 67, p. 148; 

78, p. 65

(MH3BC1) “ “ Manganese 1,050 0.03 5, pp. 67, 72, 204, 1042; 76, p. 23; 

78, p. 12; 82, p. 3

Notes:

Sample ID Smurfit-Stone, Source/Soil, Sequential sample number (e.g., 01), 0 to 2 feet below ground surface (Ref. 5, p. 20). 

ID Identification

SQL Sample Quantitation Limit: for metals = (IDL or MDL x (Final volume/(sample weight x % solids) x dilution factor; for dioxins/furans = (CRQL/% solids) x 

dilution factor (Ref. 78)

CRQL Contract required quantitation limit

IDL Instrument Detection Limit

MDL Method Detection Limit

CLP Contract Laboratory Program

pg/g picograms per gram (equivalent to parts per trillion) 

mg/kg milligrams per kilogram (equivalent to parts per million)

TCDD Tetrachlorodibenzo-p-dioxin

PeCDD Pentachlorodibenzo-p-dioxin

HxCDD Hexachlorodibenzo-p-dioxin

HpCDD Heptachlorodibenzo-p-dioxin

TCDF Tetrachlorodibenzofuran

PeCDF Pentachlorodibenzofuran
33 

Hazardous Substances Associated with Source No. 1 through Chemical Analysis: 

2,3,7,8-TCDD

1,2,3,7,8-PeCDD

1,2,3,6,7,8-HxCDD

1,2,3,4,6,7,8-HpCDD

Total-TCDD

2,3,7,8-TCDF

2,3,4,7,8-PeCDF

Arsenic

Cadmium

Lead

Manganese

2.2.3 Hazardous Substances Available to a Pathway 

Source No. 1 comprises four piles at the Smurfit-Stone Mill property. Source No. 1 samples contain 

2,3,7,8-TCDD; 1,2,3,7,8-PeCDD; 1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8-HpCDD; Total-TCDD; 2,3,7,8-

TCDF; 2,3,4,7,8-PeCDF; arsenic; cadmium; lead; and manganese (Ref. 5, pp. 403, 404, 416-418, 1006-

1011, 1038-1045; Table 1 of this HRS documentation record). 

None of the ponds constituting Source No. 1 were found to be lined during soil boring activities 

performed during the combined SI and RA conducted in October 2011 (Ref. 77, pp. 2, 3, 5, 10-13). 

Ground water wells were installed into the surficial alluvial aquifer at a few of these boring locations 

(e.g., SSGW03, SSGW04 and SSGW07) and ground water samples from these wells reveal the presence 

of many of these same hazardous substances in the ground water beneath, or just downgradient of the 

source, evidence that hazardous substances have migrated from the source area (Ref. 5, pp. 33, 68, 71, 74-

76, 193, 390, 882, 911; Table 4C of this HRS documentation record). 

Containment: 

Release to ground water: 

The sludge ponds were unlined; therefore, a ground water containment factor of 10 is assigned for Source 

No. 1 (Refs. 1, pp. 51595-51596, Table 3-2, 51629, Section 4.2.2.1.2; 22, p. 44; 77, pp. 2, 3, 5, 10-13).
34 

Containment Description

Containment 

Factor Value References

Gas release to air: NS NS

Particulate release to air: NS NS

Release to ground water: source unlined 10 5, pp. 33, 68, 71, 75, 193; 21, pp. 15-16, 

21, 25-27; 22, pp. 3, 44; 77, pp. 2, 3, 5, 

10-13. 

Release to surface water via overland 

migration and/or flood:

NS NS

Release to surface water via ground water

to surface water:

10 5, pp. 33, 68, 71, 75, 193; 21, pp. 15-16, 

21, 25-27; 22, p. 3; 77, pp. 2, 3, 5, 10-13.

Notes:

NS Not Scored

2.4.2 Hazardous Waste Quantity (HWQ)

2.4.2.1.1 Hazardous Constituent Quantity (Tier A)

The hazardous constituent quantity for Source No. 1 could not be adequately determined according to the 

HRS requirements; that is, the total mass of all CERCLA hazardous substances in the source is not known 

and cannot be estimated with reasonable confidence (Ref. 1, p. 51591 [Section 2.4.2.1.2]). There are 

insufficient historical and current data (e.g., manifests, State records, waste concentration sampling data, 

etc.) available to adequately calculate the total mass of all CERCLA hazardous substances in the source 

and the associated releases from the source. 

Therefore, there is insufficient information to evaluate the associated releases from the source to calculate 

the hazardous constituent quantity for Source No. 1 with reasonable confidence. Scoring, therefore, 

proceeds to the evaluation of Tier B, hazardous wastestream quantity. 

Hazardous Constituent Quantity Assigned Value: Not evaluated. 

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

For the reasons stated in Section 2.4.2.1.1 above, there is insufficient information to evaluate the 

associated releases from the source to calculate the hazardous wastestream quantity for Source No. 1 with 

reasonable confidence, as required by Reference 1, Section 2.4.2.1.2, p. 51591. Scoring, therefore,

proceeds to the evaluation of Tier C, volume. 

Hazardous Wastestream Quantity Assigned Value: Not Evaluated. 

2.4.2.1.3 Volume (Tier C)

The volume of each of the four sludge ponds was determined from a document entitled “Pond Statistics” 

produced by the Smurfit-Stone Mill, as well as information gathered during the 2011 combined SI and 

RA (Refs. 5, p. 37; 50, p. 1). 

Reference 50 contains pond dimensions that were supplied to the Missoula City-County Health 

Department by the former Smurfit-Stone Mill. The volume data from Reference 50 will be used to assign 

the HRS Volume Assigned Value below. 
35 

Source Type Description - dimensions Units (yd3) References

pile sludge pond 3

volume in acre-feet: 160 

volume in yd3: 160 x 1613* = 258,080 

Volume: 258,080 50, p. 1 

pile sludge pond 4

volume in acre-feet: 230 

volume in yd3: 230 x 1613* = 370,990 

Volume: 370,990 50, p. 1 

pile sludge pond 5

volume in acre-feet: 336 

volume in yd3: 336 x 1613* = 541,968 

Volume: 541,968 50, p. 1 

pile sludge pond 17

volume in acre-feet: 173 

volume in yd3: 173 x 1613* = 279,049

Volume: 279,049 50, p. 1 

* 1 acre foot = 1,613 cubic yards (yd3) 

The sum of the volume of the four sludge ponds at the Smurfit-Stone Mill is: 

 (258,080 yd3

) + (370,990 yd3) + (541,968 yd3) + (279,049 yd3) = 1,450,087 yd3

Sum: 1,450,087 yd3

Equation for Assigning Value (Ref. 1, Table 2-5): Volume/2.5 

1,450,087 / 2.5 = 580,034.8 

Volume Assigned Value: 580,034.8 

2.4.2.1.4 Area (Tier D)

Area (Tier D) is assigned a value of zero when the volume of the source can be determined (Ref. 1, p. 

51591, Section 2.4.2.1.3).

Area Assigned Value: 0 

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source HWQ value for Source No. 1 is 580,034.8 for Tier C – Volume (Ref. 1, Table 2-5, p. 51591, 

Section 2.4.2.1.5).

Source No. 1 HWQ Value: 580,034.8 
36 

2.2.1 Source Identification (Continued)

Number of source: Source No. 2 

Name of source: Emergency spill pond 8 

Source Type: Surface Impoundment 

Location of Source (with reference to a map of the site): The emergency spill pond 8 (surface 

impoundment) is located in the central portion of the Smurfit-Stone Mill property, to the west of the 

industrial core area, as can be seen in Figure 2 of this HRS documentation record.

Pond 8 was originally one of the wastewater ponds at the Smurfit-Stone Mill and is shown as such in the 

EIS reports for the expansion of the mill published in 1974, 1985, and 1986 (Refs. 21, pp. 17, 21; 26, p. 6; 

38, pp. 2, 5). When pond 8 became formally designated the ‘emergency spill pond’, and began to capture 

spills, is not clear from available documents. In 1974 all discharges (or ‘sewers’) from the three main 

process areas of the mill (e.g., pulp mill and recovery, paper mill, and the bleach plant) are shown to 

report directly to the clarifier, with no discrete flow to a spill pond being depicted (Ref. 21, p. 16). 

However, the presence of a spill pond (for accidental spills of petroleum or chemicals) was noted during a 

1993 EPA inspection (Ref. 25, p. 49), and is also shown in the flow diagram for the MPDES permit 

application in 2004 (Ref. 22, p. 26) and in a wastewater system overview from 2009 (Ref. 50, pp. 1-2). 

In approximately 1992, pond 8 was divided into two ‘cells’: a larger, active ‘wet’ cell on the north and a 

smaller ‘dry’ cell on the south (Refs. 48, p. 21; 51, pp. 11, 15; Figure 2 of this HRS documentation 

record). The two cells were shown as being connected between 1974 and 1985 (Refs. 21, p. 17; 26, p. 6). 

The two cells have a combined surface area of approximately 24 acres, an average depth of 5 feet, and a 

capacity of approximately 120 acre-feet (Ref. 50). 

The ‘sewers’ leading from the pulp mill and the paper mill were both continuously monitored for flow 

rate and conductivity to identify process upsets or spills (Ref. 22, p. 8). The 1993 EPA inspection report 

listed a single accidental release of sulfuric acid that had occurred at the mill in March 1991 (Ref. 25, p. 

52). Records concerning the dates, quantities, and constituents of any other spills that may have occurred, 

and been directed to the emergency spill pond, have not been identified. 

The first storage ponds that processed wastewater also acted as clarifiers, providing treatment for the 

wastewater (Ref. 22, p. 5). As a result of (and to prevent additional) accumulation of sludge in the storage 

ponds, a primary clarifier was constructed at the Smurfit-Stone Mill in 1969-1970 (Ref. 22, p. 5). Prior to 

the construction and operation of the clarifier, wastewater containing sludge was temporarily held in 

wastewater storage ponds (as well as directly discharged to the Clark Fork River) (Ref. 22, p. 5). Pond 8 

is shown as a wastewater storage pond in the EIS reports for the expansion of the mill published in 1974, 

1985, and 1986, and therefore would have accumulated sludge in its bottom during its use (Refs. 21, pp. 

17, 21; 26, p. 6). The presence of sludge in the emergency spill pond was confirmed by a subsurface 

boring (SSSO13) placed within the ‘dry cell’ of the emergency spill pond during the combined SI and RA 

conducted in October 2011 (Refs. 77, p. 14; 79, p. 11). This boring revealed that no liner existed between 

the sludge and the underlying, in situ alluvial material (Refs. 77, p. 14; 79, p. 11).

At the time of the EPA-START PA investigation of June 2011, the ‘wet’ cell of pond 8 had free liquids 

present (Ref. 48, pp. 21, 64, 65, 66). No evidence of a liner, or functioning leachate collection and 

removal system above a liner was observed at the emergency spill pond during either the June 2011 PA 

investigation, or during the combined SI and RA investigation conducted in October 2011 (Ref. 77, pp. 

14). No cover over the pond was present (Refs. 48, pp. 64-68; 79, p. 3). A breach through the dike (into 
37 

pond 9) was noted in the northwest corner of the ‘wet’ cell, showing that the diking was unsound (Ref. 

48, pp. 21, 66; Figure 2 of this HRS documentation record). 

In October 2011, EPA-START conducted a combined site inspection and removal assessment at the 

Smurfit-Stone Mill property (Ref. 5, p. 7). Field activities included the collection of five samples from 

directly within the emergency spill pond 8, with samples being collected from each cell (Ref. 5, pp. 21-

22, 73, 78; Figure 3 of this HRS documentation record). Two of the samples were replicates collected for 

QA/QC purposes. Four of these samples were collected from 0 to 2 feet bgs and one was collected from 

below 2 feet bgs (Ref. 5, pp. 20-22, 73, 78). Samples collected from the emergency spill pond were moist, 

organic-rich, dark grey to black, non-cohesive, fibrous and with a sulfur odor (Refs. 5, p. 186; 77, p. 14; 

79, p. 11). 

Five of these samples will be used to characterize Source No. 2 (Ref. 5, pp. 406, 417, 418, 1046-1048, 

1050-1051). These samples contained hazardous substances, including: 2,3,7,8-TCDD; 1,2,3,7,8-PeCDD; 

1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8-HpCDD; Total-TCDD; 2,3,7,8-TCDF; 2,3,4,7,8-PeCDF; and 

manganese (Ref. 5, pp. 30-32, 60; Table 2 of this HRS documentation record). 

2.2.2 Hazardous Substances

EPA-START collected the source samples listed in Table 2 during the October 2011 combined SI and RA

at the Smurfit-Stone Mill property (Ref. 5, p. 7). Five samples were collected from Source No. 2 during 

the same sampling event (Ref. 5, pp. 21-22, 72-73, 78; Figure 3 of this HRS documentation record). Four 

of these samples were collected from 0 to 2 feet bgs and the remaining sample was collected from below 

2 feet bgs (Ref. 5, pp. 20, 21, 72, 73, 78). All five samples will be used to characterize Source No. 2. 

All Source No. 2 samples were collected with disposable plastic scoops either from a plastic core sleeve 

emplaced into the source material with a hydraulic-push machine or, in places that the machine could not 

safely access, directly from the surface of the source being sampled (Ref. 5, pp. 21, 25, 186, 189). All 

plastic sleeves and scoops used during the project were new, certified clean, single-use disposable sleeves 

and scoops that were used once (Ref. 5, pp. 25, 57, 205, 210). 

A steel shovel was used at some locations to break up the surface material (e.g., if it was frozen) to ease 

the collection of the samples with plastic scoops (Ref. 5, p. 25). The shovel was decontaminated prior to 

its initial use and then between sampling locations where it was used as per EPA-START TSOP 4.11 

“Equipment Decontamination” (Ref. 53, pp. 13, 14). A rinsate blank was collected from the shovel to 

document thoroughness of the decontamination procedures and to determine if any cross-contamination 

occurred (Ref. 5, pp. 25, 187). Results from the rinsate sample show that cross-contamination did not 

occur (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134). 

For the deeper location where a hydraulic-push machine was used to first collect source material into a 

plastic sleeve, the same stainless steel cutting shoe was used for each location. The cutting shoe is the 

only reusable part of the sampling system that makes contact with in situ soils. The drilling subcontractor 

decontaminated the cutting shoe prior to its initial use and then between sampling locations using a 

method equivalent to that in TSOP 4.11. A rinsate blank (sample SSSW89) was collected from both the 

shovel and the cutting shoe to assess the quality and thoroughness of the decontaminating procedures 

used (Ref. 5, pp. 25, 54, 78, 187). The analytical results from this rinsate sample showed no 

concentrations of contaminants of concern (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134). 

All samples from Source No. 2 were analyzed for dioxins and furans using EPA Method 8290A by the 

private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for total TAL metals using 

ICP-AES using method CLP-ISM01.3 by the EPA CLP RAS laboratory, Chemtech Consulting Group, 
38 

Inc., in Mountainside, New Jersey. EPA-START contractor TechLaw, Inc. reviewed all dioxin and furan 

data according to the “National Functional Guidelines for Chlorinated Dibenzo-p-dioxins (CDDs) and 

Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all metals data in 

accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic 

Superfund Data Review,” January 2010 (Ref. 5, pp. 7-9, 27, 52, 53, 408, 410, 1022, 1024).

Sample-specific quantitation limits have been calculated for each Source No. 2 analytical result and are 

listed in Table 2 of this HRS documentation record (Refs. 1, p. 51586; 78, pp. 14-17, 31, 33, 35-40).

Logbook notes regarding sample collection details, including sample collection dates, are provided in 

Reference 5 (pp. 195-215). The chain-of-custody records are provided in Reference 76 (pp. 1-39) and 

Reference 67 (pp. 148-149). The locations of all samples are depicted in Figure 3 of this HRS 

documentation record, and are described in Reference 5 (pp. 73, 78).

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 

4, 5; 44, p. 1-5; 45, p. 3). The Smurfit-Stone Mill produced bleached pulp and paper from 1960 through 

1999 (Refs. 16, p. 1; 21, pp. 7, 13, 16; 22, pp. 7, 9; 25, p. 9; 26, p. 5). In a study performed by the EPA 

where wastewater effluent from bleaching kraft mills was sampled, 90 of 107 samples (84 percent) 

contained detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent) contained detectable 

quantities of 2,3,7,8-TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent) 

collected from bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of 

the 97 samples contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8). 

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine 

mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted 

CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8-

PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27). 

Analytical results from the sampling of the emergency spill pond on the Smurfit-Stone Mill property 

show that a number of dioxin and furan compounds are present (Ref. 5, pp. 67, 69, 73, 78, 406, 417-418; 

Table 2 of this HRS documentation record). 

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by 

pulp and paper mills through the TRI database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with 

the highest TWPE reported for both types of mills (Ref. 44, p. 4-8). Wood is a major source of manganese 

in the kraft process (Ref. 44, p. 6-20). The Smurfit-Stone Mill (known at that time as Stone Container 

Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6). 

The presence of metals in wastewater discharge from the mill was noted in the EIS for the mill, and total 

manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample 

collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Ref. 22, pp. 56, 61, 81). 

Analytical results from the sampling of the emergency spill pond on the Smurfit-Stone Mill property 

show that manganese is present in the pond (Refs. 5, pp. 67, 69, 73, 78, 1047-1048, 1050-1051; Table 2 

of this HRS documentation record). 
39 

TABLE 2: Source Samples - Source No. 2 (Emergency Spill Pond 8) (Collected October 2011)

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit (SQL)

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

SSSO1402 10/28/11 wet cell 1,2,3,4,6,7,8-

HpCDD

157 101.05 5, pp. 67, 73, 205, 417; 67, p. 149; 

78, p. 31 

(MH3BC7) “ “ Manganese 1,470 0.03 5, pp. 67, 73, 205, 1048; 76, p. 23; 

78, p. 14; 82, p. 3

SSSO8902 (replicate 

of SSSO1402)

“ “ 1,2,3,4,6,7,8-

HpCDD

128 105.77 5, pp. 67, 78, 205, 418;

78, p. 33 

67, p. 149; 

(MH3BC9) “ “ Manganese 1,580 0.03 5, pp. 67, 78, 205, 1050; 76, p. 23; 

78, p. 15; 82, p. 3

SSSO1302 10/28/11 dry cell 2,3,7,8-TCDD 1.22 0.97 5, pp. 67, 73, 205, 406;

78, p. 35 

67, p. 148; 

“ “ “ 1,2,3,6,7,8-

HxCDD

4.24 2.50 5, pp. 67, 73, 205, 406;

78, p. 35

67, p. 148; 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

72.7 2.86 5, pp. 67, 73, 205, 406; 67, p. 148; 

78, p. 35

“ “ “ Total-TCDD 6.84 0.97 5, pp. 67, 73, 205, 406; 67, p. 148; 

78, p. 36

“ “ “ 2,3,7,8-TCDF 5.58 1.20 5, pp. 67, 73, 205, 406;

78, p. 36 

67, p. 148; 

“ “ “ 2,3,4,7,8-PeCDF 2.18 0.45 5, pp. 67, 73, 205, 406;

78, p. 36 

67, p. 148; 

(MH3BC5) “ Manganese 1,870 0.07 5, pp. 67, 73, 205, 1046; 76, p. 23; 

78, p. 16; 82, p. 3

SSSO9902 (replicate 

of SSSO1302)

10/28/11 “ 1,2,3,7,8-PeCDD 1.12 0.65 5, pp. 67, 78, 205, 418; 67, p. 149; 

78, p. 37 

“ “ “ 1,2,3,6,7,8-

HxCDD

6.05 1.19 5, pp. 67, 78, 205, 418;

78, p. 37

67, p. 149; 
40 

TABLE 2: Source Samples - Source No. 2 (Emergency Spill Pond 8) (Collected October 2011)

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit (SQL)

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

92.8 2.44 5, pp. 67, 78, 205, 418; 67, p. 149; 

78, p. 37 

“ “ “ Total-TCDD 8.12 0.66 5, pp. 67, 78, 205, 418; 67, p. 149; 

78, p. 38 

“ “ “ 2,3,7,8-TCDF 5.67 0.94 5, pp. 67, 78, 205, 418; 67, p. 149; 

78, p. 38

“ “ “ 2,3,4,7,8-PeCDF 0.938 0.30 5, pp. 67, 78, 205, 418; 67, p. 149; 

78, p. 38

(MH3BD0) “ “ Manganese 1,560 0.05 5, pp. 67, 78, 205, 1051; 76, p. 23; 

78, p. 16; 82, p. 3

SSSO1306 10/28/11 “ 1,2,3,4,6,7,8-

HpCDD

8.46 0.40 5, pp. 67, 73, 205, 417; 67, p. 149; 

78, p. 39

“ “ “ Total-TCDD 0.405 0.08 5, pp. 67, 73, 205, 417; 67, p. 149; 

78, p. 40

(MH3BC6) “ “ Manganese 104 0.04 5, pp. 67, 73, 205, 1047; 76, p. 23;

78, p. 17; 82, p. 3 

Notes:

Sample ID Smurfit-Stone, Source/Soil, Sequential sample number (e.g., 01), 0 to 2 feet below ground surface (Ref. 5, p. 20). 

ID Identification

SQL Sample Quantitation Limit: for metals = IDL or MDL x (final volume/(sample weight x % solids) x dilution factor; for dioxins/furans = (CRQL/% solids) x 

dilution factor (Ref. 78)

CRDL Contract required detection limit

IDL Instrument detection limit

MDL Method detection limit

CLP Contract Laboratory Program

pg/g picograms per gram (equivalent to parts per trillion) 

mg/kg milligrams per kilogram (equivalent to parts per million)

TCDD Tetrachlorodibenzo-p-dioxin

PeCDD Pentachlorodibenzo-p-dioxin
41 

HxCDD Hexachlorodibenzo-p-dioxin

HpCDD Heptachlorodibenzo-p-dioxin

TCDF Tetrachlorodibenzofuran

PeCDF Pentachlorodibenzofuran
42 

Hazardous Substances Associated with Source No. 2 through Chemical Analysis: 

2,3,7,8-TCDD

1,2,3,7,8-PeCDD

1,2,3,6,7,8-HxCDD

1,2,3,4,6,7,8-HpCDD

Total-TCDD

2,3,7,8-TCDF

2,3,4,7,8-PeCDF

Manganese

2.2.3 Hazardous Substances Available to a Pathway 

Source No. 2 consists of one surface impoundment (emergency spill pond 8) at the Smurfit-Stone Mill 

property (see Figure 2 of this HRS documentation record). Source No. 2 samples contain 2,3,7,8-TCDD; 

1,2,3,7,8-PeCDD; 1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8-HpCDD; Total-TCDD; 2,3,7,8-TCDF; 2,3,4,7,8-

PeCDF; and manganese (Ref. 5, pp. 406, 417, 418, 1046, 1047, 1048, 1050-1051) (See Table 2 of this 

HRS documentation record). 

As seepage was one of the principal methods of discharge of wastewater from the mill since its inception 

(Ref. 22, p. 3), it follows that none of the wastewater storage ponds, including the emergency spill pond 

8, would have been lined (Ref. 21, pp. 15, 16, 21, 25, 27). A soil boring (SSSO13) was placed through the 

sludge and into the underlying in situ alluvial material in the dry cell of the emergency spill pond 8 during 

the combined SI and RA conducted in October 2011 (Ref. 5, pp. 21, 67, 69, 73). No liner was identified 

in the soil boring (Ref. 77, p. 14). 

Ground water samples collected from two wells (SSGW11 and SSGW15) completed in the surficial

alluvial aquifer immediately adjacent to and downgradient of Source No. 2 reveal the presence of 

manganese in the ground water (Ref. 5, pp. 75-76, 917, 953; Table 4C of this HRS documentation 

record).

Containment: 

Release to ground water: 

The emergency spill pond 8 was unlined; therefore, a ground water containment factor of 10 is assigned 

for Source No. 2 (Refs. 1, pp. 51595-51596 (Table 3-2), 51629, Section 4.2.2.1.2; 21, pp. 15-16, 21, 25-

27; 22, pp. 3, 44; 77, p. 14).
43 

Containment Description

Containment 

Factor Value References

Gas release to air: NS NS

Particulate release to air: NS NS

Release to ground water:

Source unlined 

10 5, pp. 21, 67, 69, 73, 75-76, 78, ; 21, pp. 

15-16, 21, 25-27; 22, pp. 3, 44; 77, p. 14 

Release to surface water via overland 

migration and/or flood:

NS NS

Release to surface water via ground 

water to surface water: 

10 5, pp. 21, 67, 69, 73, 75-76, 78, ; 21, pp. 

15-16, 21, 25-27; 22, p. 3; 77, p. 14 

Notes:

NS Not Scored

2.4.2 Hazardous Waste Quantity (HWQ)

2.4.2.1.1 Hazardous Constituent Quantity (Tier A) 

The hazardous constituent quantity for Source No. 2 could not be adequately determined according to the 

HRS requirements; that is, the total mass of all CERCLA hazardous substances in the source is not known 

and cannot be estimated with reasonable confidence (Ref. 1, pp. 51590-51591 [Section 2.4.2.1.1]). There 

are insufficient historical and current data (e.g., manifests, state records, waste concentration sampling 

data, etc.) available to adequately calculate the total mass of all CERCLA hazardous substances in the 

source and the associated releases from the source. 

Therefore, there is insufficient information to evaluate the associated releases from the source to calculate 

the hazardous constituent quantity for Source No. 2 with reasonable confidence. Scoring, therefore,

proceeds to the evaluation of Tier B, hazardous wastestream quantity. 

Hazardous Constituent Quantity Assigned Value: Not evaluated. 

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

For the reasons stated in Section 2.4.2.1.1 above, there is insufficient information to evaluate the 

associated releases from the source to calculate the hazardous wastestream quantity for Source No. 2 with 

reasonable confidence, as required by Reference 1, Section 2.4.2.1.2, p. 51591. Scoring, therefore,

proceeds to the evaluation of Tier C, volume. 

Hazardous Wastestream Quantity Assigned Value: Not Evaluated. 

2.4.2.1.3 Volume (Tier C)

The volume of the emergency spill pond 8 was determined from a document entitled “Pond Statistics” 

produced by the Smurfit-Stone Mill, as well as information gathered during the 2011 combined SI and 

RA (Refs. 5, p. 37; 50). 

Reference 50 contains pond dimensions that were supplied to the Missoula City-County Health 

Department by the former Smurfit-Stone Mill. The volume data from Reference 50 will be used to assign 

the HRS Volume Assigned Value below. 
44 

Source Type Description - dimensions Units (yd3) References

surface 

impoundment 

emergency spill pond 8

volume in acre-feet: 120 

volume in yd3

: 120 x 1613* = 193,560 

Volume: 193,560 50, p. 1 

* 1 acre foot = 1,613 cubic yards (yd3) 

Equation for Assigning Value (Ref. 1, Table 2-5): Volume/2.5 

193,560 / 2.5 = 77,424 

Volume Assigned Value: 77,424 

2.4.2.1.4 Area (Tier D)

Area (Tier D) in assigned a value of zero when the volume of a source can be determined, as required by 

Reference 1, Section 2.4.2.1.3, p. 51591. 

Area Assigned Value: 0 

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source HWQ value for Source No. 2 is 77,424 for Tier C – Volume (Ref. 1, Table 2-5, p. 51591, 

Section 2.4.2.1.5).

Source HWQ Value: 77,424 
45 

2.2.1 Source Identification (Continued)

Number of source: Source No. 3 

Name of source: Wastewater storage pond 2

Source Type: Surface Impoundment 

Location of Source (with reference to a map of the site): Wastewater storage pond 2 (surface 

impoundment) is located in the southwest corner of the Smurfit-Stone Mill property, to the southwest of 

the industrial core area, adjacent to the Clark Fork River, as can be seen in Figure 2 of this HRS 

documentation record.

Wastewater storage pond 2 was one of the wastewater ponds at the Smurfit-Stone Mill and is shown as 

such in the EIS reports for the mill published in 1974, 1985, and 1986 (Refs. 21, pp. 17, 21; 26, p. 6; 38, 

p. 5). The first storage ponds that processed wastewater also acted as clarifiers, providing treatment for 

the wastewater (Ref. 22, p. 5). As a result of (and to prevent additional) accumulation of sludge in the 

storage ponds, a primary clarifier was constructed at the Smurfit-Stone Mill in 1969-1970 (Ref. 22, p. 5).

Prior to the construction and operation of the clarifier, wastewater containing sludge was temporarily held 

in wastewater storage ponds (as well as directly discharged to the Clark Fork River) (Ref. 22, p. 5). 

Wastewater pond 2, therefore, would have accumulated sludge during its use (Refs. 21, pp. 17, 21; 26, p. 

6). 

At the time of the EPA-START PA investigation of June 2011 and the combined SI and RA conducted in 

October 2011, wastewater storage pond 2 was mostly dry, with standing water present in a few places and 

large areas of vegetation (Refs. 5, p. 191; 48, p. 53). No evidence of a liner or functioning leachate 

collection and removal system above a liner was observed at the pond, and the pond did not have a 

maintained engineered cover (Refs. 5, p. 191; 48, p. 53; 79, p. 6).

The pond has a surface area of approximately 121 acres, an average depth of 11.7 feet, and a capacity of 

approximately 1,414 acre-feet (Refs. 5, p. 37; 50). Standing water was present on the surface of the pond 

in a photo dated June 10, 2011 (Ref. 48, p. 53. Pond is present along bottom of photo). 

In October 2011, EPA-START, conducted a combined SI and RA at the Smurfit-Stone Mill property 

(Ref. 5, p. 7). Field activities included the collection of two samples from directly within pond 2 (Ref. 5, 

pp. 22, 67, 69, 73; Figure 3 of this HRS documentation record). Both samples were collected from 0 to 2 

feet bgs (Ref. 5, pp. 25, 73). The samples collected from the wastewater pond 2 were primarily sandy and 

clayey silt with blebs of dark, organic material and pieces of wood (Refs. 5, p. 200; 79, p. 6). 

Both of these samples will be used to characterize Source No. 3. These samples contained hazardous 

substances, including: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD); 1,2,3,7,8-pentachlorodibenzo-pdioxin (PeCDD); 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD); 2,3,7,8-tetrachlorodibenzofuran 

(TCDF); 2,3,4,7,8-pentachlorodibenzofuran (PeCDF); and manganese (Ref. 5, pp. 30-34, 60, 67, 69, 200, 

404, 1036-1037; Table 3 of this HRS documentation record). 

2.2.2 Hazardous Substances

EPA-START collected the source samples listed in Table 3 during the October 2011 combined SI and RA

at the Smurfit-Stone Mill property (Ref. 5, p. 7). Two samples were collected from Source No. 3 during 

the same sampling event (Ref. 5, pp. 22, 73; Figure 3 of this HRS documentation record). Both of these 
46 

samples were collected from 0 to 2 feet bgs and both will be used to characterize Source No. 3 (Ref. 5, 

pp. 20, 22, 73). 

Both Source No. 3 samples were collected with disposable plastic scoops directly from the surface of the 

source being sampled (Ref. 5, pp. 21-22, 25; Ref. 79, p. 6). All plastic scoops used during the project 

were new, certified clean, single-use disposable scoops that were used once (Ref. 5, pp. 25, 57, 200, 210). 

A steel shovel was used at some locations to break up the surface material (e.g., if it was frozen) to ease 

the collection of the samples with plastic scoops (Ref. 5, p. 25). The shovel was decontaminated prior to 

its initial use and then between sampling locations where it was used as per EPA-START TSOP 4.11 

“Equipment Decontamination” (Ref. 53, pp. 13, 14). A rinsate blank was collected from the shovel to 

document thoroughness of the decontamination procedures and to determine if any cross-contamination 

occurred (Ref. 5, pp. 25, 54, 78, 187). Results from the rinsate sample show that cross-contamination did 

not occur (Ref. 5, pp. 114, 121, 122, 125-126, 130-132, 134). 

Both samples from Source No. 3 were analyzed for dioxins and furans using EPA Method 8290A by the 

private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for total TAL metals using 

ICP-AES using method CLP-ISM01.3 by the EPA CLP RAS laboratory, Chemtech Consulting Group, 

Inc., in Mountainside, New Jersey. EPA-START contractor TechLaw, Inc. reviewed all dioxin and furan 

data according to the “National Functional Guidelines for Chlorinated Dibenzo-p-dioxins (CDDs) and 

Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all metals data in 

accordance with “USEPA Contract Laboratory Program National Functional Guidelines for Inorganic 

Superfund Data Review,” January 2010 (Ref. 5, pp. 7, 8, 9, 52, 53, 394, 395, 397, 1022, 1024).

Sample-specific quantitation limits have been calculated for each Source No. 3 analytical result and are 

listed in Table 3 of this HRS documentation record (Refs. 1, p. 51586; 78, pp. 17-18, 26-30). Logbook 

notes regarding sample collection details, including sample collection dates, are provided in Reference 5

(pp. 195-215). The chain-of-custody records are provided in Reference 76 (pp. 1-39) and Reference 67 (p. 

154). The locations of all samples are depicted in Figure 3 of this HRS documentation record, and are 

described in Reference 5 (pp. 72, 73). 

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 

4, 5; 44, p. 1-5; 45, p. 3). The Smurfit-Stone mill produced bleached pulp and paper from 1960 through 

1999 (Refs. 16, p. 1; 21, p. 34; 22, pp. 7, 9; 25, p. 9; 26, p. 5). In a study performed by the EPA where 

wastewater effluent from bleaching kraft mills was sampled, 90 of 107 samples (84 percent) contained 

detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent) contained detectable quantities 

of 2,3,7,8-TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent) collected from 

bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of the 97 samples 

contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8). 

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine 

mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted 

CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8-

PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27). 

Analytical results from the sampling of wastewater storage pond 2 on the Smurfit-Stone Mill property 

show that a number of dioxin and furan compounds are present (Ref. 5, pp. 67, 69, 73, 404; Table 3 of 

this HRS documentation record). 

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by 

pulp and paper mills through the TRI database (Ref. 44, pp. xvi, 1-1, 4-8). Manganese was the metal with 
47 

the highest TWPE reported for both types of mills (Ref. 44, pp. xvi, 4-8). Additionally, wood has been

noted as a major source of manganese in the kraft process (Ref. 44, p. 6-20). The Smurfit-Stone Mill 

(known at that time as Stone Container Corporation) was one of the mills for which TRI data was 

compiled (Ref. 44, p. A-6). 

The presence of metals in wastewater discharge from the mill was noted in the EIS for the mill, and total 

manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample 

collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Refs. 22, pp. 61, 81). 

Analytical results from the sampling of wastewater storage pond 2 on the Smurfit-Stone Mill property 

show that manganese is present in the pond (Ref. 5, pp. 67, 69, 73, 1036, 1037; Table 3 of this HRS 

documentation record).
48 

TABLE 3: Source Samples - Source No. 3 (Wastewater Storage Pond 2) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit (SQL)

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

SSSO1502 10/25/11 wastewater 

storage 

pond 2

2,3,7,8-TCDD 4.76 0.15 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 26 

“ “ “ 1,2,3,7,8-PeCDD 3.61 0.37 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 27

“ “ “ 1,2,3,6,7,8-

HxCDD

15.0 0.86 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 27 

“ “ “ 1,2,3,4,6,7,8-

HpCDD

67.4 0.91 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 27 

“ “ “ Total-TCDD 10.3 0.14 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 28 

“ “ “ 2,3,7,8-TCDF 7.98 0.38 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 28

“ “ “ 2,3,4,7,8-PeCDF 0.756 0.24 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 28

(MH30S4) “ “ Manganese 238 0.04 5, pp. 67, 73, 200, 1036, 1065; 76, 

p. 36; 78, p. 17

SSSO1602 10/25/11 “ 2,3,7,8-TCDD 1.14 0.09 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 29

“ “ “ 1,2,3,6,7,8-

HxCDD

2.88 0.27 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 29

“ “ “ 1,2,3,4,6,7,8-

HpCDD

13.2 0.47 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 29 

“ “ “ Total-TCDD 1.32 0.08 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 30

“ “ “ 2,3,7,8-TCDF 2.84 0.14 5, pp. 67, 73, 200, 404; 67, p. 154; 

78, p. 30
49 

TABLE 3: Source Samples - Source No. 3 (Wastewater Storage Pond 2) (Collected October 2011) 

Sample Location 

and private lab ID

(CLP Sample ID for 

metals) 

Sample 

Collection 

Date

Location 

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/g) 

(metals-mg/kg)

Sample 

Quantitation 

Limit (SQL)

(dioxins/furanspg/g) 

(metals-mg/kg) 

References 

(MH30S5) “ “ Manganese 98.2 0.04 5 pp. 67, 73, 200, 1037, 1065; 76, 

p. 36; 78, p. 18 

Notes:

Sample ID Smurfit-Stone, Source/Soil, Sequential sample number (e.g., 01), 0 to 2 feet below ground surface (Ref. 5, p. 20). 

ID Identification

SQL Sample Quantitation Limit: for metals = IDL x (final volume/(sample weight x % solids)) x dilution factor; for dioxins/furans = (CRQL/% solids) x dilution factor

(Ref. 78)

CRQL Contract Required Quantitation Limit

IDL Instrument Detection Limit

CLP Contract Laboratory Program

pg/g picograms per gram (equivalent to parts per trillion) 

mg/kg milligrams per kilogram (equivalent to parts per million)

TCDD Tetrachlorodibenzo-p-dioxin

PeCDD Pentachlorodibenzo-p-dioxin

HxCDD Hexachlorodibenzo-p-dioxin

HpCDD Heptachlorodibenzo-p-dioxin

TCDF Tetrachlorodibenzofuran

PeCDF Pentachlorodibenzofuran
50 

Hazardous Substances Associated with Source No. 3 through Chemical Analysis: 

2,3,7,8-TCDD

1,2,3,7,8-PeCDD

1,2,3,6,7,8-HxCDD

1,2,3,4,6,7,8-HpCDD

Total-TCDD

2,3,7,8-TCDF

2,3,4,7,8-PeCDF

Manganese

2.2.3 Hazardous Substances Available to a Pathway

Source No. 3 consists of one surface impoundment (wastewater storage pond 2) at the Smurfit-Stone Mill 

property (see Figure 2 of this HRS documentation record). Source No. 3 samples contain 2,3,7,8-TCDD; 

1,2,3,7,8-PeCDD; 1,2,3,6,7,8-HxCDD; 1,2,3,4,6,7,8-HpCDD; Total-TCDD; 2,3,7,8-TCDF; 2,3,4,7,8-

PeCDF; and manganese (Ref. 5, pp. 404, 1036, 1037) (see Table 2 of this HRS documentation record). 

As seepage was one of the principal methods of discharge of wastewater from the mill since its inception 

(Ref. 22, pp. 3, 5), it follows that none of the ponds, including wastewater pond 2, would have been lined 

(Ref. 21, pp. 15, 16, 21, 25-27). 

Contamination of ground water caused by the disposal of wastewater through storage ponds was formally 

recognized by 1974 and has been acknowledged by the mill (Refs. 21, pp. 36, 37, 39; 38, p. 10; 51, pp. 1, 

18). A 2004 report related to ground water beneath the property notes that the ground water beneath the 

ponds is generally similar in quality to the treated process wastewater in the storage ponds (Ref. 59, p. 

11).

A ground water sample collected from a well (SSGW13) completed in the surficial alluvial aquifer 

immediately adjacent to and downgradient of Source No. 3 reveals the presence of manganese in the 

ground water (Ref. 5, pp. 76, 951; 59, p. 52; Table 4C and Figure 3 of this HRS documentation record).

This indicates that the hazardous substance manganese has migrated from this source.

Containment: 

Release to ground water: 

The wastewater ponds, including wastewater storage pond 2, were unlined; therefore, a ground water 

containment factor of 10 is assigned for Source No. 3 (Refs. 1, pp. 51595-51596 (Table 3-2), 51629, 

Section 4.2.2.1.2); 21, pp. 15-16, 21, 25-27; 22, pp. 3, 44).
51 

Containment Description Containment Factor Value References

Gas release to air: NS NS

Particulate release to air: NS NS

Release to ground water: Source unlined 10 21, pp. 15-16, 21, 25-27, 

36-37, 39; 22, pp. 3, 44; 

38, p. 10; 51, pp. 1, 18 

Release to surface water via overland 

migration and/or flood:

NS NS

Release to surface water via ground water

to surface water: 

10 21, pp. 15-16, 21, 25-27, 

36-37, 39; 22, p. 3; 38, p. 

10; 51, pp. 1, 18

Notes:

NS Not Scored

2.4.2 Hazardous Waste Quantity (HWQ)

2.4.2.1.1 Hazardous Constituent Quantity (Tier A) 

The hazardous constituent quantity for Source No. 3 could not be adequately determined according to the 

HRS requirements; that is, the total mass of all CERCLA hazardous substances in the source is not known 

and cannot be estimated with reasonable confidence (Ref. 1, pp. 51590-51591 [Section 2.4.2.1.1]). There 

are insufficient historical and current data (e.g., manifests, state records, waste concentration sampling 

data, etc.) available to adequately calculate the total mass of all CERCLA hazardous substances in the 

source and the associated releases from the source. 

Therefore, there is insufficient information to evaluate the associated releases from the source to calculate 

the hazardous constituent quantity for Source No. 3 with reasonable confidence. Scoring, therefore,

proceeds to the evaluation of Tier B, hazardous wastestream quantity. 

Hazardous Constituent Quantity Assigned Value: Not evaluated. 

2.4.2.1.2 Hazardous Wastestream Quantity (Tier B)

For the reasons stated in Section 2.4.2.1.1 above, there is insufficient information to evaluate the 

associated releases from the source to calculate the hazardous wastestream quantity for Source No. 3 with 

reasonable confidence, as required by Reference 1, Section 2.4.2.1.2, p. 51591. Scoring, therefore,

proceeds to the evaluation of Tier C, volume. 

Hazardous Wastestream Quantity Assigned Value: Not Evaluated. 

2.4.2.1.3 Volume (Tier C)

The volume of wastewater pond 2 was determined from a document entitled “Pond Statistics” produced 

by the Smurfit-Stone Mill (Ref. 50). 

Reference 50 contains pond dimensions that were supplied to the Missoula City-County Health 

Department by the former Smurfit-Stone Mill. The volume data from Reference 50 will be used to assign 

the HRS Volume Assigned Value below. 
52 

Source Type Description - dimensions Units (yd3) References

surface 

impoundment 

wastewater storage pond 2

volume in acre-feet: 1,414 

volume in yd3

: 1,414 x 1613* = 2,280,782 

Volume: 2,280,782 50, p. 1 

* 1 acre foot = 1,613 cubic yards (yd3) 

Equation for Assigning Value (Ref. 1, Table 2-5): Volume/2.5 

2,280,782 / 2.5 = 912,312.8 

Volume Assigned Value: 912,312.8 

2.4.2.1.4 Area (Tier D)

Area (Tier D) is assigned a value of zero when volume of a source can be determined, as required by 

Reference 1, Section 2.4.2.1.3, p. 51591. 

Area Assigned Value: 0 

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source HWQ value for Source No. 3 is 912,312.8 for Tier C – Volume (Ref. 1, Table 2-5, p. 51591, 

Section 2.4.2.1.5).

Source HWQ Value: 912,312.8 
53 

SUMMARY OF SOURCE DESCRIPTIONS

Source 

No.

Source 

Hazardous 

Waste 

Quantity

Value

Source 

Hazardous 

Constituent 

Quantity 

Complete? 

(Y/N)

Containment Factor Value by Pathway

Groundwater

(GW)

(Ref. 1, 

Table 3-2) 

Surface Water (SW) Air

Overland/ 

flood 

(Ref. 1, 

Table 4-2)

GW to SW 

(Ref. 1, 

Table 3-2) 

Gas

(Ref. 1, 

Table 6-3) 

Particulate 

(Ref. 1, 

Table 6-9) 

1 580,034.8 No 10 NE 10 NE NE

2 77,424 No 10 NE 10 NE NE

3 912,312.8 No 10 NE 10 NE NE

Sum of 

values* 1,569,772 

Notes: 

NE Not evaluated

* In accordance with Section 2.4.2.2 of the HRS (Ref. 1, p. 51591), the sum of the factor values is rounded to the nearest 

integer. 
54 

2.5 Other Possible On-Site Sources 

Wastewater Aeration Basins (I, II, and III), Polishing Ponds (North and South), and Additional 

Wastewater Storage Ponds (1, 1A, 7, 9, 10, 11, 12, 13, 13A, 16, 18) 

Given the interconnected nature of the wastewater flow paths at the facility (particularly prior to the 

installation of the primary clarifier) and the hazardous substances already identified within the sludge 

ponds, the emergency spill pond 8, and the wastewater storage pond 2 (Sources 1, 2 and 3); it is possible 

that the three aeration basins, two polishing ponds, and the remaining wastewater storage ponds at the 

mill would have similar types and concentrations of hazardous substances to those identified in Sources 1, 

2 and 3 through chemical analysis (e.g., dioxins, furans, and metals including manganese) (Refs. 5, pp. 

30-32, 67, 69, 72-73, 78, 403, 404, 416-418, 1006-1011, 1036-1050; 21, p. 16; 22, pp. 5-10, 25-30; 26, p. 

13; Tables 1, 2 and 3 of this HRS documentation record). 

Aeration basins I and II were constructed in 1974-1975, while aeration basin III (formerly pond 14) was 

constructed in 1990 (Refs. 22, p. 9; 26, pp. 6, 12; 48, p. 21; 50, pp. 1-2). In addition to aeration, 

supplemental nutrients (nitrates and phosphates) were added to the basins to enhance and maintain 

bacterial populations to assist with water treatment (Refs. 22, p. 9; 26, p. 12). The three basins have a

combined surface area of 56 acres, an average depth of 12 feet, and a total capacity of approximately 670 

acre-feet (Ref. 50). 

The north polishing pond (formerly wastewater storage pond 15) and south polishing pond (formerly part 

of wastewater storage pond 14) were used for further settling of biological solids after aeration of the 

wastewater (Refs. 21, p. 17; 22, p. 9; 26, p. 6; Ref. 50, pp. 1-2). The two polishing ponds have a 

combined surface area of 43 acres, an average depth of 7.6 feet, and a total capacity of 328 acre-feet (Ref. 

50). 

After polishing, treated wastewater was diverted to additional storage ponds prior to discharge from 3 

outfalls to the Clark Fork River (Ponds 1, 1A, 2, 7, 9, 10, 11, 12, 13, 13A, 16, 18) (Ref. 22, pp. 9, 27, 44). 

The 12 ponds have a combined surface area of 707 acres, an average depth of approximately 8 feet, and a 

total capacity of 5,772 acre-feet (Ref. 50). Surface materials within one of these ponds (wastewater 

storage pond 2) were sampled as part of the combined SI and RA conducted at the property in October 

2011, and this pond is considered Source No. 3 within this HRS documentation record. 

In total, the above basins and ponds have a combined surface area of approximately 806 acres and total 

capacity of approximately 6,770 acre-feet (Ref. 50).

Additional evidence of transport of material from the sources includes a breach through the dike at the 

northwest corner of the emergency spill pond 8 (Source No. 2) into wastewater storage pond 9, which was 

noted during the 2011 PA field reconnaissance (Ref. 48, pp. 21, 66; 79, p. 2). A photo taken during the 

combined SI and RA in October 2011 shows that a lobe of material was deposited through the breach and 

into wastewater spill pond 9 (Ref. 79, p. 2). In addition, a breach through the dike at the western corner of 

Sludge Pond 5 (part of Source No. 1) was also noted during the 2011 PA field reconnaissance (Ref. 79, p. 

5). The circumstances behind these breaches are not currently known. 

These breaches show that it is possible that hazardous substances documented to be present in both 

sources through chemical analysis (See Tables 1 and 2 of this HRS documentation record) have been 

transported and deposited within other areas of the mill. 
55 

Landfills at Areas D and E 

According to a Stone Container Corporation document, ‘Area D’ (also variously identified as landfill or 

pond 19, located adjacent to Landfill C) and ‘Area E’ (also variously identified as landfill or pond 20, 

located between Landfills C and F) contained primary and secondary sludge (Ref. 51, pp. 9, 15). Of note, 

Area E was also identified as a rapid infiltration pond in the EIS completed in1986 (Ref. 26, p. 6). 

Given that sludge has been reportedly disposed of in Areas D and E, it is possible that these areas would 

have similar types and concentrations of hazardous substances to those identified in Source 1 through 

chemical analysis (e.g., dioxins, furans, and metals including manganese) (Ref. 5, pp. 403, 404, 417-418, 

1006-1011, 1038-1045; Table 1 of this HRS documentation record). 
2 1

!

3 4

E

I

B

K

J

H

G

D

C

C

F

A

D

D

D

D

D

D

D

D

D

D

D

D

D

D

!?

!?

!?

!?

!?

!?

!?

!?

!?

!>

!>

!>

!>

!>

!>

!>

!>

!> !>

!>

!>

!>

!>

Sludge

17

Emergency Spill 

Pond 8

¬·

¬·

¬· Wastewater Wet Storage Pond 2 Cell Dry Cell

SSGW10, SSGW89

SSSO0702, SSSO0716

SSSO0802, SSSO0816

SSSO1202 SSSO0

SSSO8902, SSSO1402

SSS

SSSO1102, SSSO1110

SSSO

S

SSSO0602, SSSO0612

SSSO0502, SSSO0514

SSSO9902, SSSO1302,SSSO1306

SSGW14

Sludge

3

Sludge

5

Sludge

4

Polishing

Pond (South)

Landfill

20

9

10

11

7

1 1A

Aerated

Stabilization

Basins I

Aerated

Stabilization

Basins II

Polishing

Pond (North)

15

Aerated

Stabilization

Basins III

14

16

13 12

13A

18

Log

Yard

Basin

Landfill

6

Landfarm

SSGW04

SSGW07

SSGW11

SSGW08

SSGW12

SSGW13

SSGW15

SSGW16

SSGW17

SSGW18

SSGW05

SSGW03

SSSE01,SSSW01

SSSE02,SSSW02

SSSE05,SSSW05

SSSE06, SSSW06

SSSE08,SSSW08

SSSE10,SSSW10

SSSE07

SSSE09

SSSE03

RM

198

RM

195

RM

197

RM

196

C l a rk

F o rk

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Author: Alex Mahrou Date/Time: Thursday, March 21, 2013 2:02:15 PM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figure_3_Source_Observed_Release814.mxd

0 0.25 0.5 0.75 1 

Miles

0 750 1,500 2,250 3,000 

Feet

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Smurfit-Stone Mill

$

ø = 272°

TDD Title:

TDD County: 

TDD State: 

Smurfit-Stone MISSOULAMT

Figure 3: Source and O

Release Samp

Data Sources:Property Features: Refs. 26, p.6; 50,p.2;51, p.15; 59, p. 46Source Data: Ref. 5, pp. 15, 21,22, 66, 67, 72, 74 - 78River Miles: Ref. 6, p. 4Outfalls: Ref. 22, p. 44

RM = River Mile

Ground Water Observed Release Samples

Surface Water and SedimentObserved Release Samples

Sources Source Samples

Samples

Key

A Landfill AB Effluent ClarifierC Landfill CD Landfill 19 D

E Hog Fuel AreaF Landfill F

G Landfill G

H Non-Contact Cooling Water Ditch

I Paper & Pulp Mill

J Wood Chip Conveyor System

Color Removal Plant

>!

!?

D

Source no. 1Source no. 2Source no. 3

K

1 Outfall 1

2 Outfall 2

3 Outfall 3

4 Outfall 4

Numbered Ponds and Landfills

LandfillsTreated Wastewater Storage PondsAerated Stabilization Basins Treatment PondsPolishing PondsSludge PondsEmergency Spill Pond

Mill Property BoundaryProperty FeaturesRiver miles
57 

4.0 SURFACE WATER MIGRATION PATHWAY

4.0.1 Migration Components 

The surface water migration pathway score for the Smurfit-Stone Mill is based on the ground water to 

surface water migration component, as described in Section 4.2 below (Ref. 1, pp. 51604-51605, Section 

4.0.1). The ground water to surface water migration component is used to evaluate surface water threats 

that result from migration of hazardous substances from source(s) to surface water via ground water, as 

has occurred at the Smurfit-Stone Mill. 

Given that many of the wastewater storage ponds (e.g., other possible sources) at the property, including 

Source No. 3, lie within the 100-year flood plain for the Clark Fork River, the overland/flood migration to 

surface water component is likely complete at this site (Refs. 63; 71; Figures 1 and 2 of this HRS 

documentation record). In addition, for many years the Smurfit-Stone Mill directly discharged wastewater 

to the Clark Fork River through three outfalls (Refs. 22, pp. 10, 27, 44; 26, p. 6). These outfalls are 

considered probable points of entry (PPEs) for the entry of hazardous substances from the three identified 

sources into the river, as well as from the other possible sources identified within Section 2.5 of this HRS 

documentation record, for the overland/flood migration component. They are not used for scoring the 

ground water to surface water migration component. 

The overland/flood migration component was not scored because the ground water to surface water 

component scores sufficiently to place the site on the NPL. 

As per the HRS, three threats exist for the surface water migration pathway through the ground water to 

surface water migration component: the drinking water threat, human food chain threat, and 

environmental threat (Ref. 1, pp. 51604-51605, Sec. 4.0.1). For the Smurfit-Stone Mill site, the human 

food chain and environmental threats are scored for the ground water to surface water migration 

component of the surface water migration pathway. These threats are discussed within Sections 4.2.3 and 

4.2.4 of this HRS documentation record. 

4.2 GROUND WATER TO SURFACE WATER MIGRATION COMPONENT

4.2.1 General Considerations

4.2.1.1 Eligible Surface Waters

According to the HRS, surface waters eligible to be scored under the ground water to surface water 

migration component must meet certain conditions. The Clark Fork River is documented to be an eligible 

surface water for the ground water to surface water migration component, as described below (Ref. 1, p. 

51626, Section 4.2.1.1). 

Condition 1:

A portion of the surface water is located within 1 mile of one or more sources at the site having a 

containment value greater than 0: 

The Clark Fork River is located approximately 2,000 feet in straight-line distance from the edge of Source 

No. 1, approximately 1,600 feet in straight-line distance from the edge of Source No. 2, and 

approximately 100 feet in straight-line distance from the edge of Source No. 3. All three of these sources 

have a containment value of 10 (Refs. 5, pp. 21, 67, 69, 73, 75-76, 78; 21, pp. 15-16, 21, 25-27, 36-37, 
58 

39; 22, p. 3; 26, p. 6; 35, p. 6; 38, p. 6; 51, pp. 1, 18; 77, pp. 2, 3, 5, 10-14; Section 2.2.3 for Sources 1, 2 

and 3 and Figure 2 of this HRS documentation record): 

Source Number Containment Value for Source Distance to Surface Water Body

(Clark Fork River)

1 10 2,000 feet

2 10 1,600 feet

3 10 100 feet

Condition 2:

The top of the uppermost aquifer (the surficial alluvial aquifer) is at or above the bottom of the surface 

water body (Clark Fork River): 

A detailed description of the geology and hydrogeology of the site is found within section 4.2.1.2 

(Definition of Hazardous Substance Migration Path for Ground Water to Surface Water Component) 

below. The pertinent information from section 4.2.1.2 is summarized here.

The uppermost aquifer beneath the Smurfit-Stone Mill property is the surficial alluvial aquifer that exists 

within the recent surficial alluvium (Unit 4 within Ref. 43, Figure 7; Refs. 58, pp. 2, 4; 59, p. 45). Ground 

water elevations were measured within existing facility monitoring wells completed in the surficial 

alluvial aquifer during the 2011 combined SI and RA (Refs. 5, pp. 24, 202, 204-206, 213-215; 72, pp. 3-

9). Two representative wells, SMW-17 and SMW-11, have been selected to demonstrate the elevation of 

the top of the uppermost aquifer. These wells have been chosen as they are in line with the general ground 

water flow direction within the aquifer (Ref. 58, pp. 5, 6; Ref. 59, pp. 52, 58, 79-82). 

For comparison to the ground water elevations within these two wells, a topographic survey of the bottom 

of the Clark Fork River was conducted in February 2013 by a geomorphologist from the University of 

Montana (Ref. 70, p. 1). The area of the river surveyed was chosen to be aligned with both of the wells

(Ref. 72, pp. 18-19). The survey consisted of a transect of 25 measurements across the river (Ref. 70, pp. 

2, 4). The average elevation of the river surface was also surveyed as part of the transect (Ref. 70, pp. 1, 

4).

The lowest elevation measured for the bottom of the Clark Fork River (i.e. its deepest point) was 3,028.64 

feet above mean sea level (amsl), measured in a side channel on the western side of the river (Ref. 70, pp. 

1, 2, 4, 5). This elevation is 7.26 feet lower than the ground water elevation measured in SMW-17 

(3,035.9), and 2.51 feet lower than the ground water elevation measured in SMW-11 (3,031.15) (Refs. 70, 

pp. 1, 2, 4, 5; 72, pp. 6, 7, 18, 19). Historic ground water elevations measured in these two wells are also 

higher than the elevation of the bottom of the river (Ref. 51, p. 23). Therefore, the condition that the top 

of the uppermost aquifer is at or above the bottom of the surface water body is met. 

It should be noted that elevations from the topographic survey conducted in February 2013 approximate 

those from the USGS published in 1963 (photorevised in 1978). Specifically, on the USGS quadrangle 

for the area, the elevation at a point on the main river channel approximately 1,000 feet upstream of the 

2013 survey is 3,030 feet amsl (Refs. 71, pp. 1, 2; 72, p. 18; Figure 2 of this HRS documentation record). 

The elevation of the main channel from the 2013 survey was between 3030.98 – 3,029.83 feet amsl (Ref. 

70, pp. 4, 5). This shows that the elevation has not significantly changed in 50 years. 

Elevation information from these wells and the bottom of the Clark Fork River is shown in the table 

below and represented graphically in Reference 72 (Refs. 70, pp. 4, 5; 72, p. 19).
59 

Location Ground/River

Surface 

Elevation 

(feet amsl)

Depth to Water 

Below Ground 

Surface - October 

2011 (feet)

Ground 

Water 

Elevation 

(feet amsl)

Lowest Bottom 

Elevation of 

Clark Fork 

River (feet amsl)

References

Well SMW-17 3050.50 14.6 3035.90 NA 51, p. 21; 72, 

pp. 6, 18, 19

Well SMW-11 3048.10 16.95 3031.15 NA 51, p. 21; 72, 

pp. 7, 18, 19 

Clark Fork 

River near

Albert Creek

3032.53 NA NA 3028.64 70, pp. 1, 2, 

4, 5 

Notes:

amsl above mean sea level

NA not applicable

Additional evidence that the bottom of the Clark Fork River is below the top of the surficial alluvial 

aquifer, namely historic ground water level data collected for the mill, is provided within the Elevation of 

Top of Uppermost Aquifer (mean sea level) discussion later in section 4.2.1.2 below. 

Condition 3:

No aquifer discontinuity is established between the source and the portion of the Clark Fork River within 

1 mile of any of the sources: 

In the vicinity of the Smurfit-Stone Mill site, the surficial alluvial aquifer is present in valley-fill alluvium 

that is continuous between the areas of the sources and the Clark Fork River (Ref. 59, pp. 8, 45 (Figure 2-

2)). There is no evidence that any geologic, topographic, or other structure or feature, that entirely 

transects the surficial alluvial aquifer and that creates a continuous boundary to ground water flow, exists 

anywhere between the sources (e.g., ponds) and the Clark Fork River. Evidence that there are no 

discontinuities between the source areas includes that all seepage water from the ponds that entered the 

shallow, surficial alluvial aquifer eventually reached the river. This, in turn, was substantiated by color 

measurements taken on the river through times of low or no direct discharge, as well as ground water 

flow measurements (Refs. 21, pp. 16, 26, 27; 22, pp. 14, 30; 26, pp. 11, 13, 94; 58, pp. 5, 6, 8, 9, 10, 11; 

59, pp. 8, 16, 22, 40-41, 51-52, 77-86). 

4.2.1.2 Definition of Hazardous Substance Migration Path for Ground Water to Surface Water Migration 

Component 

Ground Water Migration Pathway Description

The hazardous substance migration path includes both the ground water segment and the surface water inwater segment that hazardous substances would take as they migrate away from sources at the site (Ref. 

1, p. 51626). 

The ground water segment of the hazardous substance migration path begins at each source and extends 

to the PPE through the uppermost aquifer (the surficial alluvial aquifer) to the surface water (Figure 4 of 

this HRS documentation record). The PPE is defined as the point at the surface water that results from the 

shortest straight-line distance through the uppermost aquifer beneath the sources with a containment 

factor greater than zero to the surface water (Ref. 1, p. 51626, Section 4.2.1.2). There are three sources 

identified for the site, each having a PPE into the Clark Fork River (Figure 4 of this HRS documentation 

record).
60 

The ground water segment is restricted to migration via the uppermost aquifer between a source and the 

surface water (Ref. 1, p. 51626). A description of the geology and hydrogeology (both regional and sitespecific) is therefore necessary in order to evaluate this migration pathway. 

Regional Geology/Aquifer Description: 

The Smurfit-Stone Mill lies in the northwest portion of the Missoula Valley (Ref. 43, Figure 1; Figure 1 

of this HRS documentation record). The Missoula Valley is a broad northwest-trending valley that 

contains a segment of the Clark Fork River and the lowermost reach of the Bitterroot River, which joins 

the Clark Fork just west of the City of Missoula (Ref. 43, Figure 1; Figure 1 of this HRS documentation 

record). Quaternary-aged unconsolidated sand, silt and gravel in the Missoula Valley (i.e., Units 2, 3, and 

4 within Figure 7 of Reference 43) rest on top of bedrock consisting of either the Tertiary-aged 

sedimentary rocks (near to and beneath the City of Missoula) (Unit 1 within Figure 7 of Reference 43) or 

the Proterozoic-aged metamorphic rocks of the Belt Supergroup (in the northwestern portion of the 

Missoula Valley (Ref. 43, Figures 4 and 7). The unconsolidated Quaternary sand and gravel deposits in 

the center of the Missoula Valley are generally greater than 100 feet, and locally greater than 200 feet 

thick (Ref. 43). Most of the sand and gravel is interbedded with and overlain by Glacial Lake Missoula 

silt and clay, and thus was deposited before or during glacial time (Ref. 43). 

The unconsolidated deposits in the Missoula Valley contain upper (Unit 4 of Ref. 43, Figure 7) and lower 

(Unit 2 of Ref. 43, Figure 7) sand and gravel units that are separated by interbedded sand, gravel or silty 

gravel areas (Unit 3 of Ref. 43, Figure 7). This middle unit of interbedded sand, gravel or silty gravel is 

interpreted as likely being deposited as lake beds in a stand of Glacial Lake Missoula (Ref. 43). 

Quaternary sand and gravel reach thicknesses greater than 200 feet near Missoula and Frenchtown, areas 

where a deep basin-fill aquifer is present (Ref. 43). This deeper aquifer is the principal aquifer for water 

supply in the area, including the production wells for the former Smurfit-Stone Mill (Ref. 59, p. 8). 

Site Geology/Aquifer Description: 

In the immediate area of the Smurfit-Stone Mill, the geology consists of unconsolidated recent surficial 

alluvium (Unit 4 of Ref. 43, Figure 7; Figure 1 of this HRS documentation record) which overlies 

interbedded silty gravel, sand, and gravel (Unit 3 of Ref. 43, Figure 7) as described above (Ref. 43, Figure 

7). This middle unit is also reported (via drillers’ logs) to contain clay (Refs. 51, pp. 71-90; 59, p. 45). 

Beneath this lies more unconsolidated interbedded gravel and sand (Unit 2 of Ref. 43, Figure 7), which 

sits on a unit of tertiary sedimentary rocks (Ref. 43, Figure 7). Immediately to the west of the SmurfitStone Mill (and the Clark Fork River) the bedrock is comprised of the Paleozoic-aged Hasmark Dolomite 

(Refs. 43, Figures 1 and 4; 59, pp. 17, 45). 

There are two aquifer systems beneath the Smurfit-Stone Mill: the shallow-basin aquifer (also termed the 

surficial alluvial aquifer) that exists within the surficial alluvium (Unit 4 of Ref. 43, Figure 7), and the 

deeper (principal) aquifer that exists within the deeper unconsolidated interbedded gravel and sand (Unit 

2 of Ref. 43, Figure 7), and which is the principal supply of potable water in the area (Ref. 59, pp. 8, 45).

The glaciofluvial lake sediments (Unit 3 of Ref. 43, Figure 7) in between the aquifers are generally more 

fine-grained than the other two units (Refs. 58, p. 2; 59, p. 45).

-Aquifer/Stratum 1 (uppermost): Surficial Alluvial Aquifer

The uppermost aquifer beneath the Smurfit-Stone Mill property is the surficial alluvial aquifer that exists 

within the recent surficial alluvium (Unit 4 within Ref. 43, Figure 7) (Refs. 58, pp. 2, 4; 59, p. 45). The 

aquifer terminates to the west of the site at the Clark Fork River (and the bedrock on the western side of 

the river), and pinches out to the east of the mill property, where it transitions into the glaciofluvial lake 
61 

sediments within approximately 2 miles of the Clark Fork River (Unit 3 of Ref. 43, Figure 7; Ref. 59, pp. 

17, 19, 22, 44, 45). The surficial alluvium containing the aquifer continues to both the northwest and the 

southeast for at least 4 miles beyond the mill property boundary (Ref. 43, Figures 1 and 7). 

The surficial alluvium consists of poorly sorted, unconsolidated floodplain silt, sand and gravel and varies 

from approximately 15 to 41 feet thick in the vicinity of the mill, as measured from 20 shallow 

monitoring wells emplaced on mill property (Refs. 58, pp. 2, 3, 4, 5; 59, pp. 44, 45). Formation logs 

completed for these wells indicate that the alluvium is primarily composed of sand, gravel and 

cobblestones, with a general increase in the amount of clay at depth (Ref. 51, pp. 71-90). Depth to ground 

water in the wells in July-August 1991 ranged from 2.4 to 19.8 feet bgs (Ref. 58, pp. 4, 5). The hydraulic 

conductivity of the aquifer as measured from slug tests performed at this time within all 20 wells ranges 

from 120 to 1,040 feet per day (Ref. 58, p. 10). 

The surficial alluvial aquifer is not considered a major source of water in the local area, although a few 

domestic wells in the area are completed in the aquifer (Ref. 59, pp. 20, 21). Ground water flow direction 

within the surficial alluvial aquifer in the areas of the mill where the identified sources are located is 

primarily to the west towards the Clark Fork River (Ref. 58, pp. 5, 6; Ref. 59, pp. 52, 58, 79-82). During 

the winter and spring times when storage rates in the wastewater storage ponds were at their highest, 

ground water mounding created a more radial flow pattern away from the ponds (Ref. 59, pp. 85, 86). 

-Aquifer/Stratum 2 (deepest): Principal Aquifer 

The principal aquifer exists within the deeper unconsolidated interbedded gravel and sand (Unit 2 of Ref. 

43, Figure 7), and is the principal supply of potable water in the area (Ref. 59, pp. 8, 45). Domestic wells 

completed in this aquifer just north of the mill property are completed at depths ranging from 141 to 169 

feet (Ref. 59, pp. 21, 70, 72-76). Lithology information reported for these wells supports that the aquifer 

consists of gravel and sand (Ref. 59, pp. 70, 72-76). As with the surficial alluvial aquifer, the deeper 

principal aquifer terminates to the west of the mill property (at the bedrock on the western side of the 

river) (Ref. 59, p. 45). To the east of the mill property, the gravel and sands containing the aquifer abut up 

against Tertiary-aged sedimentary bedrock, although the exact extent of the aquifer in this direction is 

currently not known (Ref. 59, Figure 1). 

The aquifer is 20 to 30 feet thick locally, and pump tests have shown that the hydraulic conductivity is 

approximately 1,500 feet/day (Ref. 58, p. 2). Yields from these wells have been reported up to 60 gallons 

per minute (Ref. 59, p. 73). No information regarding the flow direction of ground water present in the 

deeper aquifer has been found.

-Local Aquifer Interconnections: 

The glaciofluvial lake sediments (Unit 3 of Ref. 43, Figure 7) in between the surficial alluvial aquifer and 

the deep principal aquifer are generally more fine-grained than the aquifers (Refs. 58, p. 2; 59, p. 45).

These sediments have been variously reported to be approximately 100 feet (Ref. 58, p. 2) or 120 to 150 

feet thick in the area of the mill (Ref. 59, pp. 22, 45). According to a report completed for the mill, pump 

test data indicate that these lake sediments have an apparent low vertical permeability of less than 0.1 

feet/day, and act as a barrier between the two aquifers (Ref. 58, p. 2). In addition, this report states that 

ground water in the deeper aquifer would tend to flow upwards to the surface (Ref. 58, p. 4). 

Conversely, the 1974 Final EIS for the mill stated that the upper and lower aquifers appear to be poorly, 

but definitely connected (Ref. 21, p. 24). The report states that hydraulic testing on the mill’s wells 

indicated the lower aquifer obtains water from the overlying zone and slightly affects water levels in the 

upper aquifer, due to aquifer leakage, although pumping of deep aquifer wells does not elicit a response in 
62 

shallow observation wells (Ref. 21, p. 24). The report also states that ‘there is also definite evidence of 

vertical movement of waste effluent from the upper shallow aquifer into the deep aquifer in the plant 

area,’ as evidenced by the detection of dissolved chemicals from waste ponds within plant production 

wells tapping the deep aquifer (Ref. 21, pp. 30, 31, 39). 

Sampling of nearby domestic wells (to the north of the site) performed on behalf of the Smurfit-Stone 

Mill have indicated that process wastewater constituents present within the shallow, surficial alluvial 

aquifer have not been found in the deep principal aquifer (Ref. 59, pp. 22, 23). Similar sampling 

performed by EPA-START in 2011 also appeared to indicate that the deeper aquifers in the vicinity of the 

domestic wells were not impacted (Ref. 5, p. 47). It should be noted however that sampling of wells 

completed in the deep aquifer located adjacent to the identified sources was not conducted (Ref. 5, p. 46).

-Local Aquifer Discontinuities

In the vicinity of the Smurfit-Stone Mill property, the surficial alluvial aquifer is present in valley-fill 

alluvium that is continuous between the areas of the sources and the Clark Fork River (Ref. 59, p. 45). 

There is no evidence that any geologic (e.g., major faults, intrusive formations such as dikes or sills), 

topographic, or other structure or feature (e.g., erosional channels and large bodies of water), that entirely 

transects the surficial alluvial aquifer and that creates a continuous boundary to ground water flow, exists 

anywhere between the sources (e.g., ponds) and the Clark Fork River (Refs. 43, Figures 1 and 7; 59, p. 

45; 71; Figure 1 of this HRS documentation record).

Evidence that there are no discontinuities between the source areas includes that all seepage water from 

the ponds that entered the shallow, surficial alluvial aquifer eventually reached the river. This, in turn, 

was substantiated by color measurements taken on the river through times of low or no direct discharge, 

as well as ground water flow measurements (Refs. 21, pp. 16, 26, 27; 22, pp. 14, 30; 26, pp. 11, 13, 94; 

58, pp. 5, 6, 8, 9, 10, 11; 59, pp. 8, 16, 22, 40, 41, 51, 52, 77-103). 

Elevation of Top of Uppermost Aquifer (mean sea level): 

The hydrogeologic units beneath the Smurfit-Stone Mill property are, from shallowest to deepest: 

surficial alluvium, the Lower or pre-Wisconsin glaciofluvial deposits (Lake Missoula sediment), and a 

deep gravel aquifer (Refs. 58, p. 2; 59, pp. 8, 45). The surficial alluvium is primarily composed of sand 

and gravel and contains the local water table (unconfined) aquifer (Refs. 58, p. 2; 59, pp. 8, 44, 45). The 

deep gravel aquifer is the principal aquifer for water supply in the area (Ref. 59, p. 8). The glaciofluvial 

lake sediments in between the aquifers are generally more fine-grained than the other two units (Ref. 58, 

p. 2). These units all extend beneath the property to the west, ending at the contact with bedrock (the 

Hasmark Dolomite) located on the west side of the Clark Fork River (Ref. 59, pp. 17, 45). The surficial 

alluvial aquifer is, therefore, the uppermost aquifer beneath the mill property (Refs. 58, p. 2; 59, pp. 8, 

45). 

Ground water elevations from monitoring wells located nearest to the source areas have been consistently 

higher than the elevation of the bottom of the Clark Fork River (Refs. 51, pp. 21-23; 58, pp. 5, 6; 59, pp. 

48, 52; 70, pp. 1, 4, 5). For example, ground water elevations of the surficial alluvial aquifer as measured 

within the monitoring well SMW-16 (the facility monitoring well located between all three sources 

identified at the site) between August 1991 and June 1992 ranged from a low of 3,040.48 feet amsl to a 

high of 3,043.21 feet amsl (Refs. 51, pp. 21-23; 59, pp. 13, 46). These elevations are 11.84 to 14.57 feet 

higher than the lowest elevation of the bottom of the Clark Fork River, as measured in February 2013 

(Refs. 51, pp. 21-23; 70, pp. 1, 4, 5). 
63 

A ground water study conducted from 2002 to 2004 showed similar results, with ground water elevations 

within wells located within the wastewater storage pond area (e.g., SMW-15, SMW-16, SMW-17, SMW19 ranging from 3,042.83 to 3,045.84 feet amsl) being 14.19 feet to 17.20 feet higher than the lowest 

elevation of the bottom of the Clark Fork River, as measured in February 2013 (Refs. 59, pp. 48, 52; 70, 

pp. 1, 4, 5). It is noted that the ground water elevation measured within the well SMW-11 in October 

2011 (3031.15 feet amsl) approximated those historically measured in this well (Refs. 51, p. 21-23; 72, 

pp. 7, 18, 19). The ground water elevation measured in the well SMW-17 in October 2011 (3035.90 feet 

amsl) was approximately 4-10 feet lower than those elevations historically measured in this well, likely 

due to the cessation of wastewater storage in the ponds surrounding this well (and the associated ground 

water mounding effect) since the closure of the mill (Refs. 51, pp. 21-23; 70, pp. 1, 2, 4, 5; 72, p. 6). 

It should be noted that elevations from the topographic survey conducted in February 2013 matches those 

from the USGS published in 1963. Specifically, on the USGS quadrangle for the area, the elevation at a 

point on the main river channel approximately 1,000 feet upstream of the 2013 survey is 3,030 feet amsl 

(Ref. 71, pp. 1, 2; Figure 1 of this HRS documentation record). The elevation of the main channel from 

the 2013 survey was 3030.98 – 3,029.83 feet amsl (Ref. 70, pp. 4, 5). This shows that the elevations have 

not significantly changed in 50 years.

Elevation of Bottom of Surface Water Body (mean sea level):

As previously discussed above, a topographic survey of the bottom of the Clark Fork River was 

conducted in February 2013 by a geomorphologist from the University of Montana (Ref. 70, p. 1). The 

area of the river surveyed was chosen to be aligned with both of the aforementioned wells (Ref. 72, pp. 

18-19). The survey consisted of a transect of 25 measurements across the river (Ref. 70, pp. 2, 4). The 

elevation of the river surface was also surveyed as part of the transect (Ref. 70, pp. 1, 4, 5).

The lowest elevation measured for the bottom of the Clark Fork River (i.e. its deepest point) was 3028.64 

feet above mean sea level (amsl), measured in a side channel on the western side of the river (Ref. 70, pp. 

1, 2, 4, 5). This elevation is 7.26 feet lower than the ground water elevation measured in SMW-17 

(3035.9 feet amsl), and 2.51 feet lower than the ground water elevation measured in SMW-11 (3031.15 

feet amsl) (Refs. 70, pp. 1, 2, 4, 5; 72, pp. 6, 7, 18, 19). 

Surface Water Probable Point of Entry and In-Water Segment Description: 

The hazardous substance migration path includes both the ground water segment and the surface water inwater segment that hazardous substances would take as they migrate away from sources at the site (Ref. 

1, p. 51626, Section 4.2.1.2). The hazardous substance migration path for the Smurfit-Stone Mill site 

begins at Source No. 3 (wastewater storage pond 2), the source with the most upstream PPE to the Clark 

Fork River (Figure 4 of this HRS documentation record). As wastewater storage pond 2 is directly 

adjacent to the Clark Fork River, the ground water segment of the hazardous substance migration path is 

only approximately 100 feet (Figure 4 of this HRS documentation record). 

The location where this PPE enters the Clark Fork River marks the beginning of the surface water inwater segment of the hazardous substance migration path for the ground water to surface water migration 

component (Ref. 1, p. 51626; Figure 5 of this HRS documentation record). From this point, the Clark 

Fork River flows generally north along the western edge of the Smurfit-Stone Mill property, passing the 

ground water to surface water PPEs1 from source No. 1, and then source No. 2 (Figure 4 of this HRS 

 

1 While shown on Figures 2, 3, and 4 of this HRS documentation record, the PPEs for the overland/flood migration 

component of the surface water migration pathway, Outfalls 1, 2 and 3, are not considered when scoring the ground 
64 

documentation record). The PPE for Source No. 2 is the lowest (most downstream) PPE for the site and is 

located approximately 1.25 miles downstream of the PPE for Source No. 3 (Figures 4 and 5 of this HRS 

documentation record). From this lowest PPE, the Clark Fork River (and therefore the migration pathway) 

then continues generally north, and then west to the end of the target distance limit (TDL) (Figure 5 of 

this HRS documentation record). The total distance from the highest PPE (most upstream) to the end of 

the TDL is approximately 16.25 miles (Ref. 1, p. 51626, Section 4.2.1.4; Figure 5 of this HRS 

documentation record).

The mean annual flow rate for the Clark Fork River as measured from a USGS gauging station located 

below Missoula, Montana (USGS station # 12353000) from the years 1930 through 2011 is 5,330 cfs 

(Ref. 60). The river is, therefore, described as a large stream to river under the HRS (Ref. 1, Table 4-13, 

p. 51613). It is shown as a perennial river on the 7.5 minute quadrangle (Ref. 71; Figure 1 of this HRS 

documentation record).

The surface water body being scored for this HRS documentation record is the Clark Fork River (a large 

stream to river). The in-water segment for HRS purposes begins at the highest upstream ground water to 

surface water PPE on the Clark Fork River and ends 15 miles downstream of the PPE from Source No. 2, 

a total distance of approximately 16.25 miles (as described above) (Figure 5 of this HRS documentation 

record).

Dilution Weight Adjustment for In-Water Segment

A dilution weight adjustment is not calculated because the inclusion of potential contamination in the 

drinking water, human food chain and environmental threats of the ground water to surface water 

migration component of the surface water migration pathway does not likely contribute significantly to 

the overall site score.

 

water to surface water migration component. 
E

I

B

K

J

H

G

D

C

C

F

A

2 1

!

3 4

Sludge

17

Emergency Spill 

Pond 8 Wastewater

Storage Pond 2

Source No. 2 PPE

Source No. 1 PPE

Source No. 3 PPE

Wet Cell

Dry Cell

199

RM

RM

198

RM

195

RM 196

Landfarm

Sludge

3

Sludge

5

Sludge

4

Polishing

Pond (South)

Landfill

20

9

10

11

7

1 1A

Aerated

Stabilization

Basins I

Aerated

Stabilization

Basins II

Polishing

Pond (North)

15 Aerated

Stabilization

Basins III

14

16

13 12

13A

18

Log Yard

Basin

Landfill

6

Production

Well Field

C l a

r

k

F o r k

O 'K e ef e Cr e e k

A lbe rt C r e ek

Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IG

Author: Alex Mahrou Date/Time: Thursday, March 21, 2013 11:22:57 AM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figure_4_PPE_GW.mxd Esri, DeLorme, NAVTEQ, TomTom

0 0.25 0.5 0.75 1 

Miles

0 950 1,900 2,850 3,800 7,600

Feet

)

Montana

Smurfit-Stone Mill

Nu

Key

A 

B C D 

E 

F 

So

$ ø = 272°

TDD Title:

TDD County: 

TDD State: 

Smurfit-Stone MISSOULA

MT

Figure 4:

Probable Poinand Ground WSegments from 

Data Sources:Property Features: Refs. 26, p.6; 50, p. 2;51, p.15; 59, p. 46Source Data: Ref. 5, pp. 15, 21,30-32, 72, 73, 78, 81-88, 100-101River Miles: Ref. 6, p. 4Outfalls: Ref. 22, p. 44 

Clark Fork River

RM 
1

2

Author: Alex Mahrou Date/Time: Thursday, March 21, 2013 4:20:48 PM File: T:\START3\Smurfit Stone Mill HRS 1207-08\GIS\maps\Figure1_SiteLoc_TDL.mxd

Target Distance Limit

Source Data:Ref. 5, pp. 21, 30-32, 72,73, 81-88, 100-101

1

2

Extent of Level II Fishery

Most Distant Level II Samples:SSSW10, SSSE10

0 0.375 0.75 1.5

Miles
67 

4.2.1.3 Observed Release of a Specific Hazardous Substance to Surface Water In-Water Segment

According to the HRS, in order to establish an observed release of an individual hazardous substance to 

surface water under the ground water to surface water migration component of the surface water 

migration pathway, an observed release both to ground water and an observed release by chemical 

analysis to surface water must be documented (Ref. 1, p. 51626, Section 4.2.1.3). The following section 

presents the necessary information to support the observed release conditions present in the surface water 

body (Clark Fork River).

Observed Release by Direct Observation to Surface Water Body: Clark Fork River

An observed release by direct observation is not being scored. However, evidence of an observed release 

includes that the direct discharge of stored wastewater occurred to the Clark Fork River through one of 

three outfalls (Refs. 22, pp. 9-10, 27; 26, p. 6). In a study performed by the EPA where wastewater 

effluent from bleaching kraft mills was sampled, 90 of 107 samples (84 percent) contained detectable 

amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent) contained detectable quantities of 2,3,7,8-

TCDF (Ref. 45, p. 5). In the same study, 94 of 97 sludge samples (97 percent) collected from bleaching 

kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of the 97 samples contained 

detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8). 

Sources of metals in pulp and paper mill waste streams include spent pulping solutions that dissolve 

metals from wood, papermaking additives such as alum and kaolin clay, soils on logs and wood chips, 

green liquor dregs (particularly for manganese), and lime used in the causticizing reaction (Ref. 44, pp. 6-

20, 6-22, 6-23). At the Smurfit-Stone Mill, the dregs from the recausticizing operation and fly ash from 

the multi-fuel boiler were both disposed of into the sludge ponds (Ref. 22, pp. 7, 8). After passing through 

the clarifier and/or sludge ponds, wastewater discharge from all portions of the paper and pulp mill, 

including from the recausticizing plant, was sent to the aeration basins and then the wastewater storage 

ponds (Ref. 22, pp. 25, 26). 

Observed Release by Chemical Analysis to Surface Water Body: Clark Fork River

In October 2011, EPA-START collected surface water and sediment samples from seven locations on the 

Clark Fork River; a background location (co-located samples SSSW04 and SSSE04), and six release 

locations (co-located samples SSSW05 and SSSE05, SSSW06 and SSSE06, SSSW07 and SSSE07, 

SSSW08 and SSSE08, SSSW09 and SSSE09, and SSSW10 and SSSE10) (Refs. 5, pp. 7, 20, 41, 68, 74; 

62, pp. 1-3; 79, pp. 7-9; Tables 4A and 4B and Figure 3 of this HRS documentation record). The 

background location samples, SSSW04 and SSSE04 were collected from the Clark Fork River 

approximately 2,700 feet upstream from Source No. 3 (i.e., wastewater storage pond 2) and 600 feet 

upstream of the confluence of O’Keefe Creek with the Clark Fork River (Refs. 62, pp. 1-3; 79, p. 7; 

Tables 4A and 4B and Figure 3 of this HRS documentation record). The release samples were collected 

from the east bank (i.e., the bank adjacent to the Smurfit-Stone Mill property) of the Clark Fork River 

from various locations over a distance of approximately 3.6 miles below the background location (Refs. 5, 

pp. 68, 74; 79, pp. 8, 9; Tables 4A and 4B and Figure 3 of this HRS documentation record). 

Specifically, SSSW05 and SSSE05 were collected adjacent to the wastewater storage pond 2 (i.e., Source 

No. 3) and approximately 0.3 mile below the highest ground water to surface water PPE (from Source No. 

3), SSSW06 and SSSE06 were collected approximately 300 feet downstream of outfall 1 and 

approximately 0.8 mile below the highest PPE, SSSW07 and SSSE07 were collected approximately 500 

feet downstream of outfall 2 and approximately 1.0 mile below the highest PPE, SSSW08 and SSSE08

were collected due west of wastewater storage pond 12 and approximately 1.8 miles below the highest 

PPE, SSSW09 and SSSE09 were collected approximately 300 feet downstream of outfall 3 and 
68 

approximately 2.5 miles below the highest PPE, and SSSW10 and SSSE10 were collected approximately 

1,000 feet downstream of outfall 4 and approximately 3.6 miles below the highest PPE (Refs. 5, pp. 73-

74, 80; 79, pp. 8, 9; Tables 4A and 4B and Figures 3 and 4 of this HRS documentation record). 

All surface water and sediment sampling was done in accordance with EPA-START TSOPs 4.17 and 

4.18 (Ref. 53, pp. 34-43). For example, at each location the surface water sample was collected before the 

sediment sample, and a new disposable plastic scoop was used to collect sediment. All samples were 

collected during the same October 2011 sampling event, over a period of two days (October 24 and 25) 

(Ref. 5, pp. 199, 210-211). All samples were collected from the east bank of the Clark Fork River, the 

side closest to the mill property (Refs. 5, pp. 7, 20, 41, 68, 74, 199, 210-211; 62, pp. 1-3; 79, pp. 7-9). 

Surface water quality parameters, such as pH, temperature, and conductivity, were measured at each 

sampling location and the results were similar at each (Ref. 5, pp. 199, 210-211). The specific areas 

sampled were backwater locations that acted as sediment traps for the finer-grained material (sands and 

silts) that were targeted for sampling (Refs. 5, p. 211; 79, pp. 7-9). All surface water samples were 

collected from 0 to 1 foot depth, and were collected before the sediment samples. All sediment samples 

were collected from material in the top 2 inches.

All samples of surface water and sediment were analyzed for dioxins and furans using EPA Method 

8290A by the private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for total and 

dissolved metals using method CLP-ISM01.3 by ICP-MS by the EPA CLP RAS laboratory, Chemtech 

Consulting Group, Inc., in Mountainside, New Jersey. EPA-START contractor TechLaw, Inc. reviewed 

all dioxin and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-pdioxins (CDDs) and Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all 

metals data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for 

Inorganic Superfund Data Review,” January 2010 (Ref. 5, p. 7-9, 52-53, 394, 397, 408, 410, 957, 959).

When compared to the upstream background surface water location (SSSW04), the release samples 

SSSW05, SSSW06, SSSW08, and SSSW10 all document an observed release by chemical analysis for 

dissolved manganese, as shown in Table 4A below (Refs. 1, p. 51589 (Table 2-3); 5, pp. 974-976, 978; 

980; Table 4A and Figure 3 of this HRS documentation record). 

When compared to the upstream background sediment location (SSSE04), the release samples SSSE05, 

SSSE06, SSSE07, SSSE08, SSSE09, and SSSE10 all document an observed release by chemical analysis 

for 1,2,3,4,6,7,8-HpCDD, as shown in Table 4B below (Refs. 1, p. 51589 (Table 2-3); 5, pp. 405-406, 

416; Table 4B and Figure 3 of this HRS documentation record). 
69 

TABLE 4A: Observed Release (Surface Water Samples) to the Surface Water In-water Segment (Clark Fork River)

Sample ID

(Date 

Collected) 

CLP 

Sample 

ID

Location on 

Clark Fork River

Sample 

Depth

(feet)

Distance from 

Highest PPE 

(miles)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(μg/L) 

Sample 

Quantitation 

Limit (SQL)

(μg/L) 

References 

Background Sample

SSSW04

(10/24/11) 

MH3102 east bank, ~600 feet 

upstream of O’Keefe 

Creek

0-1 NA Manganese 

(dissolved)

4.8 0.15 5, pp. 68, 74, 199, 974, 

1055; 53, pp. 40-43; 

62, pp. 1-3; 76, p. 39; 

78, p. 21; 79, p. 7

Contaminated Release Samples

SSSW05

(10/24/11) 

MH3103 adjacent to wastewater

storage pond 2 (Source 

No. 3) 

0-1 0.3 Manganese 

(dissolved)

30.7 0.15 5, pp. 68, 74, 210, 975, 

1055; 53, pp. 40-43; 

76, p. 39; 78, p. 21 

SSSW06

(10/24/11) 

MH3104 approximately 300 feet 

downstream of outfall 1 

0-1 0.8 Manganese 

(dissolved)

24.8 0.15 5, pp. 68, 74, 199, 976, 

1055; 53, pp. 40-43; 

76, p. 39; 78, p. 21

SSSW08

(10/25/11) 

MH3106 due west of wastewater

storage pond 12 

0-1 1.8 Manganese 

(dissolved)

32.0 0.15 5, pp. 68, 74, 211, 978, 

1056; 53, pp. 40-43; 

76, p. 39; 78, p. 21 

SSSW10

(10/25/11) 

MH3108 approximately 1,000 

feet downstream of 

outfall 4

0-1 3.6 Manganese 

(dissolved)

18.2 0.15 5, pp. 68, 74, 211, 980, 

1056; 53, pp. 40-43; 

76, p. 39; 78, p. 21

Notes:

Sample ID Smurfit-Stone, Surface Water, Sequential sample number (e.g., 01) (Ref. 5, p. 20)

ID Identification

PPE Probable Point of Entry

NA not applicable

SQL Sample Quantitation Limit: for metals = CRDL x dilution factor (Ref. 78, p. 21; Ref. 81). 

CRDL Contract required detection limit

CLP Contract Laboratory Program

μg/L micrograms per liter (equivalent to parts per billion)
70 

TABLE 4B: Observed Release (Sediment Samples) to the Surface Water In-water Segment (Clark Fork River)

Sample ID

(Date 

Collected) 

Private Lab 

Sample ID

Location on Clark Fork 

River

Depth 

(inches)

Distance 

from 

Highest 

PPE 

(miles)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(pg/g)

Sample 

Quantitation 

Limit (SQL)

(pg/g)

References

Background Sample

SSSE04

(10/24/11) 

L1080162-16 east bank, ~600 feet 

upstream of O’Keefe 

Creek

0-2 NA 1,2,3,4,6,7,8-

HpCDD

0.062 U 0.02 5, pp. 68, 74, 199, 397, 

400, 405; 62, pp. 1-3; 

67, p. 154; 78, p. 24

Contaminated Release Samples

SSSE05

(10/24/11)

L1080162-17 due west of Source No. 3 0-2 0.3 1,2,3,4,6,7,8-

HpCDD

2.34 0.09 5, pp. 68, 74, 210, 405; 

67, p. 154; 78, p. 24

SSSE06

(10/24/11)

L1080162-18 approximately 300 feet 

downstream of outfall 1

0-2 0.8 1,2,3,4,6,7,8-

HpCDD

0.698 0.12 5, pp. 68, 74,199, 405;

67, p. 154; 78, p. 25

SSSE07

(10/24/11)

L1080162-19 approximately 500 feet 

downstream of outfall 2

0-2 1.0 1,2,3,4,6,7,8-

HpCDD

1.69 0.07 5, pp. 68, 74, 210, 406; 

67, p. 154; 78, p. 25

SSSE08

(10/25/11) 

L1080162-20 due west of wastewater

storage pond 12 

0-2 1.8 1,2,3,4,6,7,8-

HpCDD

1.44 0.14 5, pp. 68, 74, 211, 416;

67, p. 154; 78, p. 25 

SSSE09

(10/25/11) 

L1080162-21 approximately 300 feet 

downstream of 

wastewater storage pond 

13A

0-2 2.5 1,2,3,4,6,7,8-

HpCDD

3.80 0.20 5, pp. 68, 74, 211, 416; 

67, p. 155; 78, p. 26 

SSSE10

(10/25/11) 

L1080162-22 approximately 1,000 feet 

downstream of outfall 4 

0-2 3.6 1,2,3,4,6,7,8-

HpCDD

2.20 0.14 5, pp. 68, 74, 211, 416; 

67, p. 155; 78, p. 26 

Notes:

Sample ID Smurfit-Stone, Sediment, Sequential sample number (e.g., 01) (Ref. 5, p. 20)

ID Identification

NA Not applicable

SQL Sample Quantitation Limit: for dioxins/furans = (CRQL/%solids) x dilution factor (Ref. 78, pp. 24-26).

CRQL Contract Required Quantitation Limit

U The material was analyzed for, but was not detected above the level of the associated value. The associated value is either the sample quantitation limit or the sample 

detection limit (Ref. 5, pp. 397, 402).

pg/g picograms per gram (equivalent to parts per trillion)

HpCDD Heptachlorodibenzo-p-dioxin
71 

Hazardous Substances Meeting Criteria for Observed Release to Surface Water In-Water Segment: 

Manganese (dissolved)

1,2,3,4,6,7,8-HpCDD

4.2.2 Drinking Water Threat

4.2.2.1 Drinking Water Threat Likelihood of Release

No drinking water intakes are located on the Clark Fork River within the downstream Target Distance 

Limit (Figure 5 of this HRS documentation record). As such, the drinking water threat was not scored 

because it is not expected to contribute significantly to the overall site score.

4.2.2.1.1 Observed Release

According to the HRS, in order to establish an observed release of an individual hazardous substance to 

surface water under the ground water to surface water migration component of the surface water pathway, 

an observed release to both ground water and an observed release by chemical analysis to surface water 

must be documented (Ref. 1, p. 51626, Section 4.2.1.3). The following section presents the necessary 

information to support the observed release conditions present in the uppermost aquifer beneath the 

Smurfit-Stone Mill (Surficial Alluvial Aquifer).

Observed Release to Ground water (Uppermost Aquifer) by Direct Observation: Surficial Alluvial 

Aquifer 

An observed release by direct observation is not being scored. 

Observed Release to Ground water (Uppermost Aquifer) by Chemical Analysis: Surficial Alluvial 

Aquifer 

The uppermost aquifer beneath the Smurfit-Stone Mill property is the surficial alluvial aquifer. It is 

described above in section 4.2.1.2 of this HRS documentation record. An observed release to ground 

water within the surficial alluvial aquifer is established by chemical analysis of monitoring well samples 

collected by EPA-START in 2011. 

In October 2011, ground water samples were collected by EPA-START from both existing and newly 

installed wells completed in the shallow, surficial alluvial aquifer (Ref. 5, pp. 7, 26, 36, 74-77). While a 

number of existing shallow ground water wells were known to be present at the Smurfit-Stone Mill 

property, most of these were located some distance away from the suspected sources at the property. For 

example, the closest existing shallow ground water monitoring well to the sludge ponds (Source No. 1) is 

monitoring well SMW-16, nearly 1,000 feet downgradient of sludge pond 4 (Ref. 59, p. 46). For this 

reason, EPA-START established additional shallow ground water monitoring wells within the surficial 

alluvial aquifer, closer to, and at some locations, directly beneath, some of the suspected sources (see 

Figure 3 of this HRS documentation record). One existing shallow well located upgradient of all sources 

at the property (well SMW-020 (sample ID: SGW01)) was chosen to represent background conditions 

(Ref. 5, pp. 30, 74; Figure 3 of this HRS documentation record). 

At each monitoring well the depth to ground water was gauged and recorded, required purge volumes 

were calculated, then the ground water was evacuated from the monitoring well in accordance with EPASTART TSOP 4.12 “Ground water Sampling” (Ref. 53, pp. 16-24). At each existing well location, a new, 
72 

disposable pump and tubing were used to purge each well. At each newly-installed well location, a 

peristaltic pump was used to purge the well, with new tubing used at each location. 

All surficial alluvial aquifer ground water samples were collected during the same October 2011 sampling 

event, over a period of four days (October 26 through 29) and by the same sampling team (Ref. 5, pp. 

213-215; 72, pp. 3-17). With the expected exception of the conductivity and salinity readings at the 

background ground water location (i.e., being indicative of unpolluted, upgradient ground water), all 

purge water quality parameters observed at each well completed in the surficial alluvial aquifer were 

similar (Ref. 5, p. 24; 72, pp. 3-17). Water at all locations (except the background location) was noted to 

be discolored, typically being brown or grey, and often smelled of sulfur (Refs. 5, pp. 213-215; 72, pp. 3-

17). 

All samples of ground water were analyzed for dioxins and furans using EPA Method 8290A by the 

private laboratory ALS Laboratory Group in Burlington, Ontario, Canada, and for total and dissolved 

metals using method CLP-ISM01.3 by ICP-MS by the EPA CLP RAS laboratory, Chemtech Consulting 

Group, Inc., in Mountainside, New Jersey. EPA-START contractor TechLaw, Inc. reviewed all dioxin 

and furan data according to the “National Functional Guidelines for Chlorinated Dibenzo-p-dioxins 

(CDDs) and Chlorinated Dibenzofurans (CDFs) Data Review September 2011” and reviewed all metals 

data in accordance with “USEPA Contract Laboratory Program National Functional Guidelines for 

Inorganic Superfund Data Review,” January 2010 (Ref. 5, pp. 7-9, 52-53, 897, 899, 957, 959; Ref. 67, p. 

1-2, 4, 160, 162).

When compared to the background ground water concentrations, observed release concentrations of 

dioxins, furans, and metals were documented in wells completed within the surficial alluvial aquifer in 

locations both directly beneath sources as well as crossgradient and downgradient of Sources No. 1, 2, 

and 3 (Table 4C of this HRS documentation record). Depth to ground water in the background well 

(SMW-20, sample ID SSGW01) was 10.77 feet bgs, while depth to ground water in the 

release/downgradient wells (SSGW03, SSGW04, SSGW05, SSGW07, SSGW08, SSGW10, SSGW11, 

SSGW12, SSGW13 (SMW-14), SSGW14 (SMW-13), SSGW16 (SMW-11), SSGW17 (SMW-19), and 

SSGW18 (SMW-10) varied from 6.5 to 26.25 feet bgs (Ref. 5, pp. 14, 24, 44; 72, pp. 3, 4, 7-17). This 

closely matches the depth to shallow ground water measured in July-August 1991 (background well = 

14.4 feet bgs, and release/downgradient wells = 2.4 to 19.8 feet bgs) (Ref. 58, pp. 4, 5), as well as those 

recorded at various times throughout 2001 to 2004 (background well SMW-20 = 8.9 to 13.0 feet bgs; and 

release/downgradient wells = 2.44 to 27.33 feet bgs) (Ref. 59, pp. 61-68). The locations of all shallow 

ground water wells sampled as part of the October EPA-START investigation are shown in Figure 3 of 

this HRS documentation record. 
73 

TABLE 4C: Observed Release (Ground Water Samples) to the Surficial Alluvial Aquifer (Ground Water Segment)

Sample 

Number 

(Date

Collected) 

EPA CLP

Sample 

Number

(for metals)

Well ID

Ground water

Elevation* 

(feet amsl)

Well 

Screened 

Interval* 

(feet amsl)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/L) 

(metals-μg/L) 

Sample 

Quantitation 

Limit (SQL)** 

(dioxins/furanspg/L) 

(metals-μg/L) 

References 

Background Sample

SSGW01

(10/26/11) 

- SMW-20 3,046.1 3,047.4-

3,032.0 

2,3,7,8-

TCDD

0.27 U 0.27 5, p. 74; 51, pp. 21, 25, 

65; 67, p. 53, 156; 72, p. 

3

“ - “ “ “ 1,2,3,6,7,8-

HxCDD

0.90 U 0.90 5, p. 74; 51, pp. 21, 25, 

65; 67, p. 53, 156; 72, p. 

3 

“ - “ “ “ 1,2,3,4,6,7,8-

HpCDD

2.91 J (29.1)¥ 1.4 5, p. 74; 49, p. 51, pp. 

21, 25, 65; 67, p. 53, 

156; 72, p. 3; 80

“ - “ “ “ Total-TCDD 0.27 U 0.27 5, p. 74; 51, pp. 21, 25, 

65; 67, p. 53, 156; 72, p. 

3

“ - “ “ “ 2,3,7,8-TCDF 0.20 U 0.20 5, p. 74; 51, pp. 21, 25, 

65; 67, p. 53, 156; 72, p. 

3

“ - “ “ “ 2,3,4,7,8-

PeCDF

0.44 U 0.44 5, p. 74; 51, pp. 21, 25, 

65; 67, p. 53, 156; 72, p. 

3

“ MH3109 “ “ “ Arsenic

(dissolved)

1.6 0.14 5, pp. 74, 981, 1066; 51, 

pp. 21, 25, 65; 72, p. 3; 

76, p. 38; 78, p. 20 

“ “ “ “ “ Lead

(dissolved)

1.0 U 0.05 5, pp. 74, 960, 964, 981, 

1066; 51, pp. 21, 25, 65; 

72, p. 3; 76, p. 38; 78, p. 

20
74 

TABLE 4C: Observed Release (Ground Water Samples) to the Surficial Alluvial Aquifer (Ground Water Segment)

Sample 

Number 

(Date

Collected) 

EPA CLP

Sample 

Number

(for metals)

Well ID

Ground water

Elevation* 

(feet amsl)

Well 

Screened 

Interval* 

(feet amsl)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/L) 

(metals-μg/L) 

Sample 

Quantitation 

Limit (SQL)** 

(dioxins/furanspg/L) 

(metals-μg/L) 

References 

“ “ “ “ “ Manganese

(dissolved)

1.1 U 0.15 5, pp. 74, 960, 964, 981; 

51, pp. 21, 25, 65; 72, p. 

3; 76, p. 38; 78, p. 21

Contaminated Release Samples

SSGW03

(10/28/11) 

MH3BA1 SSGW03 3,052.5 3046.7-

3036.7 

Arsenic 

(dissolved)

26.2 0.14 5, pp. 75, 911; 72, p. 16;

76, p. 24; 77, p. 2; 78, p. 

20; 82, p. 3

“ “ “ “ “ Manganese

(dissolved)

1,100 0.15 5, pp. 75, 911; 72, p. 16;

76, p. 24; 77, p. 2; 78, p. 

21; 82, p. 3

SSGW04

(10/27/11) 

- SSGW04 3,054.3 3052.1-

3042.1 

2,3,7,8-

TCDD

6.36 1.1 5, p. 75; 67, p. 199, 283; 

72, p. 10; 77, p. 3 

“ - “ “ “ 1,2,3,6,7,8-

HxCDD

51.2 2.1 5, p. 75; 67, p. 199, 283; 

72, p. 10; 77, p. 3

“ - “ “ “ 1,2,3,4,6,7,8-

HpCDD

426 5.6 5, p. 75; 67, p. 199, 283; 

72, p. 10; 77, p. 3

“ - “ “ “ Total-TCDD 152 1.1 5, p. 75; 67, p. 199, 283; 

72, p. 10; 77, p. 3

“ - “ “ “ 2,3,7,8-TCDF 35.9 2.5 5, p. 75; 67, p. 199, 283; 

72, p. 10; 77, p. 3

“ - “ “ “ 2,3,4,7,8-

PeCDF

18.6 1.1 5, p. 75; 67, p. 199, 283; 

72, p. 10; 77, p. 3

“ MH3BA2 “ “ “ Arsenic

(dissolved)

16.1 0.14 5, pp.75, 912; 72, p. 10;

76, p. 24; 77, p. 3; 78, p. 

20; 82, p. 3
75 

TABLE 4C: Observed Release (Ground Water Samples) to the Surficial Alluvial Aquifer (Ground Water Segment)

Sample 

Number 

(Date

Collected) 

EPA CLP

Sample 

Number

(for metals)

Well ID

Ground water

Elevation* 

(feet amsl)

Well 

Screened 

Interval* 

(feet amsl)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/L) 

(metals-μg/L) 

Sample 

Quantitation 

Limit (SQL)** 

(dioxins/furanspg/L) 

(metals-μg/L) 

References 

“ “ “ “ “ Manganese

(dissolved)

4,530 3.75 5, pp. 75, 912; 72, p. 10;

76, p. 24; 77, p. 3; 78, p. 

21; 82, p. 3 

SSGW05

(10/27/11)

- SSGW05 3,047.5 3,051.0-

3,041.0

2,3,7,8-

TCDD

4.18 3.4 5, p. 75; 67, p. 200, 283; 

72, p. 11; 77, p. 4

“ - “ “ “ 1,2,3,4,6,7,8-

HpCDD

546 13 5, p. 75; 67, p. 200, 283; 

72, p. 11; 77, p. 4 

“ - “ “ “ Total-TCDD 4.18 3.4 5, p. 75; 67, p. 200, 283; 

72, p. 11; 77, p. 4 

“ MH3BA3 “ “ “ Arsenic

(dissolved)

31.0 0.14 5, pp. 75, 913; 72, p. 11;

76, p. 24; 77, p. 4; 78, p. 

20; 82, p. 3

“ “ “ “ “ Manganese

(dissolved)

726 0.15 5, pp. 75, 913; 72, p. 11;

76, p. 24; 77, p. 4; 78, p. 

21; 82, p. 3

SSGW07

(10/28/11) 

MH3BA4 SSGW07 3,047.9 3,046.4-

3,026.4 

Arsenic

(dissolved)

32.4 0.14 5, pp. 75, 914; 72, p. 15;

76, p. 24; 77, p. 5; 78, p. 

20; 82, p. 3 

“ “ “ “ “ Manganese

(dissolved)

9,240 3.75 5, pp. 75, 914; 72, p. 15; 

76, p. 24; 77, p. 5; 78, p. 

21; 82, p. 3

SSGW08

(10/28/11) 

MH3BA5 SSGW08 3026.5 3,029.0-

3,009 

Arsenic

(dissolved)

95.9 0.14 5, pp. 75, 915; 76, p. 24; 

72, p. 12; 77, p. 6; 78, p. 

20; 82, p. 3 

“ “ “ “ “ Lead 

(dissolved)

1.7 0.05 5, pp. 75, 915; 76, p. 24; 

72, p. 12; 77, p. 6; 78, p. 

20; 82, p. 3
76 

TABLE 4C: Observed Release (Ground Water Samples) to the Surficial Alluvial Aquifer (Ground Water Segment)

Sample 

Number 

(Date

Collected) 

EPA CLP

Sample 

Number

(for metals)

Well ID

Ground water

Elevation* 

(feet amsl)

Well 

Screened 

Interval* 

(feet amsl)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/L) 

(metals-μg/L) 

Sample 

Quantitation 

Limit (SQL)** 

(dioxins/furanspg/L) 

(metals-μg/L) 

References 

“ “ “ “ “ Manganese

(dissolved)

4,790 3.75 5, pp. 75, 915; 76, p. 24; 

72, p. 12; 77, p. 6; 78, p. 

21; 82, p. 3 

SSGW10

(10/28/11) 

MH3BA6 SSGW10 3041.5 3020.6-

3010.6 

Arsenic 

(dissolved)

121 0.14 5, pp. 75, 916; 72, p. 14; 

76, p. 24; 77, p. 7; 78, p. 

20; 82, p. 3

“ “ “ “ “ Manganese

(dissolved)

1,320 0.15 5, pp. 75, 916; 72, p. 14;

76, p. 24; 77, p. 7; 78, p. 

21; 82, p. 3

SSGW89 

(duplicate 

of 

SSGW10) 

(10/28/11)

MH3BB4 “ “ “ Arsenic 

(dissolved)

109 0.14 5, pp. 75, 77, 924; 72, p. 

14; 76, p. 27; 77, p. 7; 

78, p. 20; 82, p. 3 

“ “ “ “ “ Manganese

(dissolved)

1,180 0.15 5, pp. 75, 77, 924; 72, p. 

14; 76, p. 27 77, p. 7; 

78, p. 21; 82, p. 3

SSGW11

(10/28/11) 

MH3BA7 SSGW11 3,034.6 3,016.8-

3,006.8 

Arsenic 

(dissolved)

90.4 0.14 5, pp. 75, 917; 72, p. 13;

76, p. 24; 77, p. 8; 78, p. 

20; 82, p. 3 

“ “ “ “ “ Lead 

(dissolved)

4.6 0.05 5, pp. 75, 917; 72, p. 13; 

76, p. 24; 77, p. 8; 78, p. 

20; 82, p. 3

“ “ “ “ “ Manganese

(dissolved)

4,260 3.75 5, pp. 75, 917; 72, p. 13; 

76, p. 24; 77, p. 8; 78, p. 

21; 82, p. 3
77 

TABLE 4C: Observed Release (Ground Water Samples) to the Surficial Alluvial Aquifer (Ground Water Segment)

Sample 

Number 

(Date

Collected) 

EPA CLP

Sample 

Number

(for metals)

Well ID

Ground water

Elevation* 

(feet amsl)

Well 

Screened 

Interval* 

(feet amsl)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/L) 

(metals-μg/L) 

Sample 

Quantitation 

Limit (SQL)** 

(dioxins/furanspg/L) 

(metals-μg/L) 

References 

SSGW12

(10/29/11)

- SSGW12 3,045.2 3,033.2-

3,023.2

1,2,3,4,6,7,8-

HpCDD

115 3.0 5, p. 76; 67, p. 205, 283; 

72, p. 17; 77, p. 9

“ MH3BA8 “ “ “ Arsenic

(dissolved)

63.3 0.14 5, pp. 76, 918; 72, p. 17;

76, p. 24; 77, p. 9; 78, p. 

20; 82, p. 3

“ “ “ “ “ Lead 

(dissolved)

8.6 0.05 5, pp. 76, 918; 72, p. 17;

76, p. 24; 77, p. 9; 78, p. 

20; 82, p. 3 

“ “ “ “ “ Manganese

(dissolved)

3,630 3.75 5, pp. 76, 918; 72, p. 17;

76, p. 24; 77, p. 9; 78, p. 

21; 82, p. 3 

SSGW13

(10/26/11) 

MH3121 SMW-14 3,033.5 3,037.9-

3,015.1 

Arsenic 

(dissolved)

35.7 0.14 5, pp. 76, 983, 1066; 51, 

pp. 21, 25, 53; 72, p. 4 ; 

76, p. 38; 78, p. 20

“ “ “ “ “ Manganese

(dissolved)

1,800 0.15 5, pp. 76, 983, 1066; 51, 

pp. 21, 25, 53; 72, p. 4; 

76, p. 38; 78, p. 21

SSGW14

(10/26/11) 

MH3122 SMW-13 3,032.4 3,038.1-

3,019.1 

Arsenic 

(dissolved)

13.0 0.14 5, pp. 76, 984, 1066; 51, 

pp. 21, 25, 51; 72, p. 5; 

76, p. 38; 78, p. 20

“ “ “ “ “ Manganese

(dissolved)

2,660 3.75 5, pp. 76, 984, 1066; 51, 

pp. 21, 25, 51; 72, p. 5; 

76, p. 38; 78, p. 21

SSGW15

(10/26/11) 

MH3123 SMW-17 3,035.9 3,041.52-

3,021.52 

Arsenic 

(dissolved)

14.5 0.14 5, pp. 76, 985, 1066; 51, 

pp. 21, 25, 59; 72, p. 6; 

76, p. 38; 78, p. 20
78 

TABLE 4C: Observed Release (Ground Water Samples) to the Surficial Alluvial Aquifer (Ground Water Segment)

Sample 

Number 

(Date

Collected) 

EPA CLP

Sample 

Number

(for metals)

Well ID

Ground water

Elevation* 

(feet amsl)

Well 

Screened 

Interval* 

(feet amsl)

Hazardous 

Substance

Hazardous 

Substance 

Concentration 

(dioxins/furanspg/L) 

(metals-μg/L) 

Sample 

Quantitation 

Limit (SQL)** 

(dioxins/furanspg/L) 

(metals-μg/L) 

References 

“ “ “ “ “ Manganese

(dissolved)

4,170 3.75 5, pp. 76, 985, 1066; 51, 

pp. 21, 25, 59; 72, p. 6; 

76, p. 38; 78, p. 21 

SSGW16

(10/26/11) 

MH3124 SMW-11 3,031.2 3,035.33-

3,009.03 

Arsenic 

(dissolved)

44.8 0.14 5, pp. 76, 986, 1066; 51, 

pp. 21, 24, 47; 72, p. 7; 

76, p. 38; 78, p. 20

“ “ “ “ “ Manganese

(dissolved)

3,580 3.75 5, pp. 76, 986, 1066; 51, 

pp. 21, 24, 47; 72, p. 7; 

76, p. 38; 78, p. 21

SSGW17

(10/26/11) 

- SMW-19 3,040.4 3,044.85-

3,021.65 

2,3,7,8-TCDF 2.96 0.76 5, pp. 76, 376; 51, pp. 

21, 25, 63; 67, p. 28, 

156; 72, p. 8

“ MH3125 “ “ “ Arsenic 

(dissolved)

9.2 0.14 5, pp. 76, 987, 1066; 51, 

pp. 21, 25, 63; 72, p. 8; 

76, p. 38; 78, p. 20

“ “ “ “ “ Manganese

(dissolved)

921 0.15 5, pp. 76, 987, 1066; 51, 

pp. 21, 25, 63; 72, p. 8; 

76, p. 38; 78, p. 21 

SSGW18

(10/27/11) 

MH3BA9 SMW-10 3,029.4 3,032.98-

3,006.98 

Arsenic 

(dissolved)

42.2 0.14 5, pp. 76, 919; 51, pp. 

21, 24, 45; 72, p. 9; 76, 

p. 24; 78, p. 20; 82, p. 3

“ “ “ “ “ Manganese

(dissolved)

3,340 3.75 5, pp. 76, 919; 51, pp. 

21, 24, 45; 72, p. 9; 76, 

p. 24; 78, p. 21; 82, p. 3

Notes:

* Elevations and screened intervals for all wells are estimated based on best available information and are rounded to the nearest 0.1 foot. 

** For dioxin and furan analytes the limit presented is an estimated detection limit (EDL). 

Sample ID Smurfit-Stone, Ground water, Sequential sample number (e.g., 01) (Ref. 5, p. 20) 
79 

ID Identification

SQL Sample Quantitation Limit: for metals = MDL x dilution factor; for dioxins/furans = EDL. MDLs can be found in Ref. 81; Ref. 67 presents the EDLs.

¥ Although not required, this ‘J’-flagged analytical result has been adjusted to illustrate the relative increase in contamination over background (Refs. 49, p. 8; 80).

MDL Method Detection Limit

CLP Contract Laboratory Program

pg/L picograms per liter (equivalent to parts per quadrillion) 

μg/L micrograms per liter (equivalent to parts per billion)

(x.x) Concentration shown in parentheses was adjusted based on its type of bias (Refs. 49; 80). 

U The material was analyzed for, but was not detected above the level of the associated value. The associated value is either the sample quantitation limit or the sample 

detection limit (Refs. 5, p. 970; 67, p. 10)

J (for dioxins and furans) Indicates that the target analyte was detected below the calibrated range (Ref. 67, p. 53). The associated numerical value is an estimated 

quantity because the Quality Control criteria were not met (Ref. 67, p. 10). 

EDL Estimated Detection Limit

TCDD Tetrachlorodibenzo-p-dioxin

PeCDD Pentachlorodibenzo-p-dioxin

HxCDD Hexachlorodibenzo-p-dioxin

HpCDD Heptachlorodibenzo-p-dioxin

TCDF Tetrachlorodibenzofuran

PeCDF Pentachlorodibenzofuran
80 

Hazardous Substances Meeting Observed Release Criteria to Ground Water (Surficial Alluvial Aquifer) 

by Chemical Analysis:

2,3,7,8-TCDD

1,2,3,6,7,8-HxCDD

1,2,3,4,6,7,8-HpCDD

Total-TCDD

2,3,7,8-TCDF

2,3,4,7,8-PeCDF

Arsenic (dissolved)

Lead (dissolved) 

Manganese (dissolved)

An observed released of site-attributable contaminants is established as outlined above in the HRS 

documentation record (Ref. 1, p. 51629, Section 4.2.2.1.1). Therefore, an observed release factor value of 

550 is assigned for the watershed (Ref. 1, p. 51629, Section 4.2.2.1.1). 

Observed Release Factor Value: 550

Additional Supporting Information 

In 1987, the EPA collected fish tissue from the Clark Fork River near Huson at river mile 1862

(approximately 10 miles below the mill) as part of the National Study of Chemical Residues in Fish study 

(previously known as the National Bioaccumulation Study) (Refs. 11, p. 1; 24, pp. 20, 21, 39 and 40 of 

Table 3; 73, pp. 2, 8, 9, 22; Figure 1 of this HRS documentation record). The sample site near Huson was 

a ‘targeted’ study site for the Smurfit-Stone Mill (then owned by the Stone Container Corporation), as it 

was thought to be a producer of dioxins due to bleaching (Ref. 73, pp. 7, 8, 10, 22). Tissue from both of 

the fish species tested (largescale sucker and rainbow trout) contained dioxins and furans (Ref. 24, p. 21, 

39 and 40 of Table 3). The concentrations were below guidelines for whole or edible fish (Ref. 24, p. 21, 

39 and 40 of Table 3). 

Attribution

The Smurfit-Stone Mill began operation as a kraft pulp mill in 1957 (Refs. 16, p. 1; 26, p. 5). Beginning 

in 1958, wastewater was temporarily stored onsite in unlined ponds before being discharged to the river 

under high flow, spring runoff conditions (e.g., March through June) (Refs. 22, pp. 5, 44; 26, pp. 7, 11).

During the storage months, a substantial amount of water seeped through the bottom of the storage ponds 

into the shallow, surficial alluvial aquifer (Ref. 22, pp. 3, 5; 26, pp. 7, 11). In fact, seepage was one of the 

principal methods of discharge of wastewater from the mill since its inception (Ref. 22, p. 3). By 1973, 

the major volume of wastewater, 10.56 mgd, was being disposed of by seepage to the shallow ground 

water, with another 5.28 mgd being discharged directly into the Clark Fork during high flow periods (Ref. 

21, pp. 15, 16, 26, 27). Ground water flow direction within the shallow, surficial alluvial aquifer in the 

areas of the mill where the identified sources are located is primarily to the west and northwest towards 

the Clark Fork River (Refs. 58, pp. 5, 6; 59, pp. 52 (Figure 4-1), 58 (Figure 4-7), 77-86 (Exhibit 1)). 

 

2 Note: the river mile reported in Reference 24 is from a different numbering system than that used by the MWFP in 

Reference 6. The Reference 6 system is used here. 
81 

-Dioxins and furans 

Bleaching pulp mills in particular are responsible for the formation of dioxins and furans (Refs. 37, pp. 2, 

4, 5; 44, p. 1-5; 45, p. 3). In 1990, the EPA published a report summarizing analytical results from the 

sampling of 104 pulp and paper mills across the U.S. that practiced chlorine bleaching of chemically

produced pulps (Ref. 45, pp. 1, 3). Samples were collected from three ‘export matrices’: bleached pulp, 

wastewater sludge, and wastewater effluent (Ref. 45, p. 3). The results of chemical analysis of the 

samples showed that, for kraft mills with bleaching operations, 2,3,7,8-TCDD was detected in 90 percent 

of overall samples, and 2,3,7,8-TCDF was detected in 97 percent of overall samples (Ref. 45, p. 4). 

Specifically for wastewater effluent samples from bleaching kraft mills, 90 of 107 samples (84 percent) 

contained detectable amounts of 2,3,7,8-TCDD and 104 of 111 samples (94 percent) contained detectable 

quantities of 2,3,7,8-TCDF (Ref. 45, pp. 4-5). In the same study, 94 of 97 sludge samples (97 percent) 

collected from bleaching kraft mills contained detectable amounts of 2,3,7,8-TCDD and 100 percent of 

the 97 samples contained detectable amounts of 2,3,7,8-TCDF (Ref. 45, pp. 5, 8). Pulp samples yielded 

similar results, with 98 of 104 (94 percent) samples of bleached kraft softwood pulp showing detectable 

levels of 2,3,7,8,-TCDD, and 99 of 102 (97 percent) samples showing detectable levels of 2,3,7,8-TCDF 

(Ref. 45, p. 5). 

None of the mills sampled were free of either compound (Ref. 45, p. 4). A subset of samples from nine 

mills were also analyzed for 2,3,7,8-substituted CDDs and CDFs. The most common 2,3,7,8-substituted 

CDDs and CDFs found across all matrices sampled were 1,2,3,4,6,7,8-HpCDD; OCDD; 1,2,3,7,8-

PeCDF; 2,3,4,7,8-PeCDF; and OCDF (Ref. 45, pp. 24-27). 

The Smurfit-Stone Mill produced bleached pulp and paper from 1960 through 1999 (Refs. 16, p. 1; 22, 

pp. 7, 9; 25, p. 9; 26, p. 5). For example, the mill produced an average of 159 tons of bleached product in 

1973 (Ref. 21, pp. 7, 13). For this year, the mill reported that 30,000 gallons of water were needed per ton 

of bleached product; therefore, the wastewater discharge from the bleach plant was computed to average 

4.8 million gallons per day (Ref. 21, p. 13).

Analytical results from the sampling of sources identified on the Smurfit-Stone Mill property show that a 

number of dioxin and furan compounds are present (Ref. 5, pp. 67, 69, 72-73, 403-404, 416-418; Tables 

1, 2 and 3 of this HRS documentation record). In particular, the dioxin compound detected in sediment 

samples collected from the Clark Fork River adjacent to the mill property, 1,2,3,4,6,7,8-HpCDD, was also 

detected in source samples at concentrations as high as 311 picograms per gram (pg/g) (sample 

SSSO0602, Table 1 of this HRS documentation record), and in the shallow ground water beneath the mill 

at concentrations as high as 546 picograms per liter (pg/L) (Refs. 5, pp. 67, 68, 72, 75, 212, 214, 403; 67, 

p. 200; 77, p. 4; 78, p. 44; sample SSGW05, Table 4C of this HRS documentation record).

In 1997, a contractor engaged by the Smurfit-Stone Mill (at that time, operated by the Stone Container 

Corporation) conducted compliance monitoring sampling for dioxins and furans in alluvial sediment and 

fish collected near the mill (Ref. 42, pp. 1, 3). Sediment composite samples were collected at one 

‘background’ location upstream of the mill (sample ID SSCS-4, “Sediment Sampling Site 4”), and at one 

location approximately 1⁄2 mile downstream of Outfall 3 (sample IDs SSCS-1 and SSCS-2 (the field 

replicate of SSCS-1)) (Ref. 42, pp. 4, 8). The samples were submitted to a laboratory and were analyzed 

for dioxin/furan congeners using EPA Method 1613A (Ref. 42, p. 9). Analytical results from the 

background sediment sample SSCS-4 contained a detectable concentration of 1,2,3,4,6,7,8-HpCDD of 4.1 

nanograms per kilogram (ng/kg) (equivalent to pg/g) while the downstream sediment samples were nondetect for this compound (Ref. 42, p. 11). The authors of the report attribute the detection of this 

compound in sample SSCS-4 to an upstream source (Ref. 42, p. 13). 
82 

It should be noted that the 1997 report did not identify other potential avenues, such as flooding of the 

Clark Fork River or atmospheric deposition from sources at the mill, as a possible reason for the presence 

of the dioxin compound. Air emissions in particular have been an issue with the mill in the past. For 

example, in a report filed by the MDEQ in early October 2011, a complainant described “a plume of dust 

coming from a settling pond just south of the former Smurfit-Stone mill.” (Ref. 57, p. 1). The pond 

located directly south of the mill is sludge pond 17, part of Source No. 1 identified in this HRS 

documentation record (Ref. 5, p. 67; Figure 2 of this HRS documentation record). The complainant 

reported that the plume was approximately 250 feet high and 0.5 mile wide (Ref. 57, p. 1). 

It should also be stressed that the sediment sampling data collected in October 2011 represents the most 

recent available data set.

Sources of metals in kraft pulp and paper mill waste streams include wood (calcium, potassium, 

manganese), spent pulping solutions that dissolve metals from wood, papermaking additives such as alum 

and kaolin clay, soils on logs and wood chips, green liquor dregs (particularly for manganese), and makeup lime used in the causticizing reaction (Ref. 44, pp. 6-20, 6-22, 6-23). At the Smurfit-Stone Mill, the 

dregs from the recausticizing operation and fly ash from the multi-fuel boiler were both disposed of into 

the sludge ponds (Ref. 22, pp. 8, 9). After passing through the clarifier and/or sludge ponds, wastewater 

discharge from all portions of the paper and pulp mill, including from the recausticizing plant, was sent to 

the aeration basins and then eventually to the wastewater storage ponds (Ref. 22, pp. 8, 9, 26, 27). These 

discharges could also bypass the clarifier and report directly to the emergency spill pond 8 (Ref. 22, p. 

26). 

The EPA published a report in November 2006 that, in part, reported on the releases of metals reported by 

pulp and paper mills through the Toxics Release Inventory (TRI) database (Ref. 44, pp. xvi, 1-1, 4-8). 

Manganese was the metal with the highest toxic-weighted pound equivalents (TWPE) reported for both 

types of mills (Ref. 44, pp. xvi, 4-8). Additionally, wood is noted to be a major source of manganese in 

the kraft process (Ref. 44, p. 6-20). The Smurfit-Stone Mill (known at that time as Stone Container 

Corporation) was one of the mills for which TRI data was compiled (Ref. 44, p. A-6). 

The presence of metals in wastewater discharged from the mill was noted in the EIS for the mill, and total 

manganese was detected at a concentration of 0.219 mg/L within a representative wastewater sample 

collected by the Smurfit-Stone Mill as part of MPDES permit requirements (Refs. 22, pp. 56, 61, 81). 

Analytical results from the sampling of sources identified on the Smurfit-Stone Mill property show that a 

number of metals including arsenic, cadmium, manganese and lead are present in the ponds (Ref. 5, pp. 

67, 69, 72-73, 1006-1011, 1036-1038-1048, 1050-1051; Tables 1, 2 and 3 of this HRS documentation 

record). In particular, manganese, which was detected in sediment samples collected from the Clark Fork 

River adjacent to the mill property, was also detected in source samples at concentrations as high as 6,840 

mg/kg (Refs. 5, pp. 67, 72, 202, 1008, 1065; 78, p. 6). Dissolved manganese was also detected in shallow 

ground water beneath the property in concentrations as high as 9,240 μg/L (Refs. 5, pp. 68, 75, 914; 77, p. 

5; 82, p. 3).

The concentration of dissolved manganese in the background surface water sample on O’Keefe Creek 

(SSSW01), collected as part of the 2011 combined SI and RA, was 4.4 micrograms per liter (μg/L), 

similar to the background dissolved manganese concentration on the Clark Fork River (sample SSSW04, 

4.8 μg/L) (Refs. 5, pp. 29, 73, 135; 62, pp. 1-3; 79, p. 7). This indicates that the elevated concentrations of 

dissolved manganese noted in the Clark Fork River adjacent to the Smurfit-Stone Mill property are not 

attributable to O’Keefe Creek.
83 

When compared to the background ground water concentrations, concentrations of manganese meeting 

HRS observed release criteria have been documented in wells completed within the surficial alluvial 

aquifer in locations both directly beneath sources as well as downgradient of Sources No. 1, 2, and 3 (Ref. 

5, pp. 911-919, 959, 960, 963, 964, 981, 983-987; and section 4.2.1.3 and Table 4C of this HRS 

documentation record). No elevated concentrations of those hazardous substances identified in ground 

water beneath the identified sources were documented in a ground water monitoring well upgradient of 

the identified sources, providing evidence that there are no other likely sources of the elevated 

concentrations documented in the surficial alluvial aquifer (Refs. 5, pp. 959, 960, 963, 964, 981; 67, p. 

53; Table 4C of this HRS documentation record). 

The Smurfit-Stone Mill is located in a rural area, surrounded primarily by agricultural land and residential 

areas to the north, east and south, and by the Clark Fork River and forest to the west (see Figure 2 of this 

HRS documentation record). No other major industrial facilities have been identified in the vicinity (i.e., 

within 3 radial miles, including upstream of the mill along O’Keefe Creek) (Ref. 61). 

Two methods were used to search for other industrial facilities that could be potential off-site sources of 

hazardous substances identified at the Smurfit-Stone Mill site or within the Clark Fork River adjacent to 

the mill (Ref. 61, pp. 1-3). First, a search of the EPA’s Facility Registration System (FRS) was conducted 

to ascertain whether any other industrial facilities existed 1), in the area immediately surrounding the mill

(i.e., within approximately 3 radial miles) to assess the potential for another facility to contribute 

contamination to ground water beneath the mill; and 2), upstream of the mill on or near (i.e., within 

approximately 0.5 mile) the Clark Fork River, to assess the potential for another facility to contribute to 

contamination of the surface water or sediments adjacent to the mill (Ref. 61, p. 1). The upstream extent 

of the search was approximately 9 miles above the Smurfit-Stone Mill property, to the location of the 

USGS Station 12353000, where the USGS has conducted water quality sampling for manganese 

(discussed on the following page of this HRS documentation record) (Ref. 65, pp. 1, 17-20). 

The FRS is a centrally managed database that identifies facilities, sites or places subject to a wide range 

of environmental regulations or that are of environmental interest (Ref. 61, p. 5). The FRS contains 

facility records that are based on information from EPA’s national program systems and state master 

facility records, including the MDEQ’s Consolidated Environmental Data Acquisition and Retrieval 

System (MT-CEDARS), which is the MDEQ’s consolidated system (Ref. 61, pp. 2, 5-6).

An initial search of the databases above yielded 483 facilities in the greater Missoula area (Ref. 61, p. 10).

These search results were vetted using the spatial parameters mentioned above (i.e., the search was 

narrowed to only those facilities within 3 miles radially, or within 9 miles upstream and on or near the 

Clark Fork). Except for the mill itself (identified within FRS as M2Green Redevelopment, Ref. 61, pp. 

17-20), this narrowed search yielded three facilities within a 3 mile radius of the mill: a stone mining and 

quarrying facility, a sign manufacturer, and a body shop (Ref. 61, pp. 21-23). Only one additional facility 

was identified upstream of the mill and within approximately 0.5 mile of the Clark Fork River, a 

construction company (Ref. 61, pp. 24-25). Further details of the methodology and search data used 

during the search of FRS are provided in Reference 61 (pp. 1-2, 5-9). Based on the distances between the 

site and the facilities mentioned above, along with the close proximity of the Smurfit-Stone Mill sources 

to the documented releases to ground water and surface water (Ref. 61, pp. 1-12, 21-25; Figure 3 of this 

HRS documentation record), it is expected that the four identified facilities are not significant contributors 

to the releases. 

The second search was conducted of records within the MDEQ Remediation Response Site Query System 

(Ref. 61, pp. 27-28). This database compiles information gathered by various state programs, including 

the Superfund program (known as the Comprehensive Environmental Cleanup and Responsibility Act 

[CECRA]), Brownfields, Enforcement, the Hazardous Waste Act Program, and others. Details for the 
84 

methods used for this search are also provided in Reference 61 (Ref. 61, p. 2-3). Of the 43 facilities 

identified by this search (Ref. 61, pp. 28-29), two facilities (the Missoula White Pine Sash Company and 

the Missoula Sawmill site) were listed as having dioxins/furans or manganese as contaminants of concern 

(Ref. 61, pp. 30, 37). MDEQ was contacted for more information about these sites and the site managers 

for both sites reported that contamination at either site had not been documented to have reached the 

Clark Fork River (Ref. 61, pp. 35-36, 40). 

In 1908, a flood washed millions of cubic yards of mine wastes (tailings) in to the Clark Fork River below 

Butte, Montana. In 1983, the EPA listed the Milltown Reservoir Sediments/ Clark Fork River site on the 

NPL due to contamination from these tailings (Ref. 64, p. 1). The Milltown Reservoir/Clark Fork River 

site has three operable units (OUs): Milltown Reservoir Sediments, Milltown Water Supply, and the 

Clark Fork River upstream of the Milltown Dam. The Milltown Dam, which was located approximately 

24 miles upstream of the Smurfit-Stone Mill at the confluence of the Clark Fork and the Blackfoot rivers, 

is the downstream extent of the NPL site (Ref. 64, pp. 1, 2, 10; Figure 1 of this HRS documentation 

record). By September 2009, the Milltown Dam and over 2.2 million cubic yards of contaminated 

sediments that had been trapped behind the dam had been removed (Ref. 65, p. 8). The primary 

contaminants of concern for the Milltown Reservoir Sediments OU are arsenic and copper; and for the 

Clark Fork River OU are arsenic, cadmium, copper, lead and zinc (Ref. 64, pp. 3, 9). 

Manganese is not a primary contaminant of concern for the Milltown Reservoir Sediments/Clark Fork 

River NPL site. USGS water quality data show that dissolved (filtered) manganese concentrations in the 

Clark Fork River increased slightly just downstream of the (now former) Milltown Dam location. 

Specifically, USGS water quality data shows that the average dissolved manganese concentration on the 

Clark Fork River above the dam (USGS Station #12334550 on the Clark Fork at Turah Bridge - 345 

samples) is 7.68 μg/L (Ref. 65, pp. 1-16; Figure 1 of this HRS documentation record). Below its 

confluence with the Bitterroot River, the average dissolved manganese concentration on the Clark Fork 

River is 8.5 μg/L (USGS Station #12353000 - 41 samples, approximately 9 miles upstream of the 

Smurfit-Stone Mill), (Ref. 65, pp. 17-20). 

The concentration of dissolved manganese in the background surface water sample (SSSW04) collected 

by EPA-START just above the mill in 2011 was 4.8 μg/L (Refs. 5, p. 974; 62, pp. 1-3; 79, p. 7; Table 4A 

and Figure 3 of this HRS documentation record). Four of six release samples (SSSW05, SSSW06, 

SSSW08, and SSSW10) collected adjacent to and just downstream of the mill showed observed release 

concentrations ranging from 18.2 to 32 μg/L (Refs. 5, pp. 975-976, 978, 980; Table 4A and Figure 3 of 

this HRS documentation record). 

4.2.3 Human Food Chain Threat

The human food chain threat is based on three factor categories: likelihood of release, waste 

characteristics, and targets. These are discussed individually in the sections below. 

4.2.3.1 Human Food Chain Threat - Likelihood of Release

As was shown above in Section 4.2.1.3 of this HRS documentation record, an observed released of siteattributable contaminants is established for both the uppermost aquifer as well as the Clark Fork River. 

Therefore, an observed release factor value of 550 is assigned for the watershed (Ref. 1, pp. 51629, 

51637, Sections 4.2.2.1.1 and 4.2.3.1). 

Likelihood of Release Factor Value: 550 
85 

4.2.3.2 Human Food Chain Threat Waste Characteristics

4.2.3.2 Human Food Chain Threat – Waste Characteristics

4.2.3.2.1 Toxicity/ mobility/ persistence/ bioaccumulation

Table 5 below summarizes the toxicity, mobility, persistence, and bioaccumulation potential factor values 

for each hazardous substance for which an observed release into the surficial alluvial aquifer has been 

established (Ref. 1, p. 51637, Section 4.2.3.2.1). As per Section 4.2.3.2.1.5 of the HRS, the substance 

with the highest toxicity/ mobility/ persistence/ bioaccumulation potential factor value is used to assign 

the toxicity/ mobility/ persistence/ bioaccumulation potential factor value for the watershed (Ref. 1, p. 

51637, Section 4.2.3.2.1.5). 1,2,3,4,6,7,8-HpCDD; 2,3,7,8-TCDF; and manganese all have a toxicity/ 

mobility/ persistence/ bioaccumulation potential factor value of 5 x 108

. 

Toxicity/ Mobility/ Persistence/ Bioaccumulation Factor value: 5 x 108

4.2.3.2.1 Toxicity/Mobility/Persistence/Bioaccumulation
86 

Table 5: Toxicity/Mobility/Persistence/Bioaccumulation Factor Values for the Human Food Chain Threat

Hazardous 

Substance

Source 

No. 

Toxicity 

Factor 

Value

(human 

food chain)

(Ref. 1, p. 

51637, 

Section 

4.2.3.2.1.1)

Mobility 

Factor 

Value*

Persistence 

Factor 

Value (for 

rivers) (Ref. 

1, p. 51637, 

Section 

4.2.3.2.1.3)

Toxicity/

Mobility/

Persistence

Factor Value 

(Ref. 1, p. 

51630, Table 

4-26) 

Bioaccumulation

Potential Factor 

Value

(Freshwater) 

(Ref. 1, p. 

51637, Section 

4.2.3.2.1.4) 

Toxicity/Mobility/ 

Persistence/Bioaccumulation 

Factor Values

(Ref. 1, Section 

4.2.3.2.1.5, Table 4-

28) 

References 

2,3,7,8-TCDD 1, 2, 3 10000 1 1 10000 5000 5 x107 1, pp. 51601-51602, 

Table 3-9; 2, p. A-330

1, 2, 3, 7, 8-

PeCDD

1, 2, 3 10000 0.0001 1 1 50000 5 x104 1, pp. 51601-51602, 

Table 3-9; 2, p. A-264

1,2,3,6,7,8-

HxCDD

1, 2, 3 10000 1 1 10000 5000 5 x107 1, pp. 51601-51602, 

Table 3-9; 2, p. A-202

1,2,3,4,6,7,8-

HpCDD

1, 2, 3 10000 1 1 10000 50000 5 x108 1, pp. 51601-51602, 

Table 3-9; 2, p. A-184

Total-TCDD 1, 2, 3 0 1 1 0 50000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-328

2,3,7,8-TCDF 1, 2, 3 10000 1 1 10000 50000 5 x108 1, pp. 51601-51602, 

Table 3-9; 2, p. A-332

2,3,4,7,8-

PeCDF

1, 2, 3 10000 1 1 10000 0.5 5 x103 1, pp. 51601-51602, 

Table 3-9; 2, p. A-268

Arsenic 1 10000 1 1 10000 5 5 x104 1, pp. 51601-51602, 

Table 3-9; 2, p. A-30

Lead 1 10000 1 1 10000 5 5 x104 1, pp. 51601-51602, 

Table 3-9; 2, p. A-224

Manganese 1, 2, 3 10000 1 1 10000 50000 5 x108 1, pp. 51601-51602, 

Table 3-9; 2, p. A-232

* As per Ref. 1, p. 51601 (Section 3.2.1.2), all substances that meet the criteria for an observed release by chemical analysis to one or more aquifers underlying the 

identified sources are assigned a mobility factor value of 1.
87 

4.2.3.2.2 Hazardous Waste Quantity

The sum of the hazardous waste quantity values for Sources 1, 2 and 3 corresponds to a hazardous waste 

quantity factor value of 1,000,000 in Table 2-6 of the HRS (Ref. 1, p. 51591). Therefore, a hazardous 

waste quantity factor value of 1,000,000 is assigned for the ground water to surface water migration 

component of the surface water pathway (Ref. 1, Sections 2.4.2.2 and 4.2.3.2.2, pp. 51591, 51592, 

51638).

Hazardous Waste Quantity Factor Value: 1,000,000 

4.2.3.2.3 Calculation of Human Food Chain Threat – Waste Characteristics Factor Category Value

The hazardous substance manganese associated with all waste sources (which all have surface water 

pathway containment factors of greater than 0 for the watershed) corresponds to a toxicity/ mobility/ 

persistence factor of 10,000 and a bioaccumulation potential factor value of 50,000 (Ref. 1, Tables 3-9, 4-

26; 2, p. A-232, Table 5 of this HRS documentation record).

(Toxicity/ mobility/ persistence factor value) x (hazardous waste quantity factor value for the watershed):

10,000 x 1,000,000 = 1 x 1010 

Subject to a maximum of 1 x 108 = 1 x 108 (Ref. 1, p. 51638, Section 4.2.3.2.3) 

 (Product above) x (bioaccumulation potential factor value for the substance)

(1 x 108

) x (50,000) = 5 x 1012 

Subject to a maximum of 1 x 1012 = 1 x 1012 (Ref. 1, p. 51638, Section 4.2.3.2.3) 

The waste characteristics product of 1 x 1012 corresponds to a waste characteristics factor category value 

of 1,000 in Table 2-7 of the HRS (Ref. 1, p. 51592, Section 2.4.3.2).

Waste Characteristics Factor Category Value: 1,000 

4.2.3.3 Human Food Chain Threat – Targets

Level I Concentrations:

No Level I concentrations have been documented.

Level II Concentrations: 

Level II concentrations of dissolved manganese and 1,2,3,4,6,7,8-HpCDD have been documented in the 

Clark Fork River, which is a fishery, as discussed below. 

According to Montana Fish, Wildlife and Parks (MFWP) and a fishing outfitter on the Clark Fork, the 

portion of the Clark Fork River adjacent to the Smurfit-Stone Mill property is fished and the fish are kept 

and consumed (Refs.11, p. 1; 40; 52, p. 1). This area is subject to contaminated ground water from Source 

Nos. 1, 2, and 3 migrating to surface water. Surface water samples collected from the river adjacent to the 

mill property during 2011 show concentrations of dissolved manganese meeting HRS observed release 

criteria (Ref. 5, pp. 975-976, 978, 980; section 4.2.1.3 and Table 4A of this HRS documentation record).

The sampling locations are shown in Figure 3 of this HRS documentation record. 

The Clark Fork River is managed by the MFWP as a cold water fishery and is heavily used by anglers and 

other water-based recreationists (Refs. 9, pp. 1, 20, 22, 24, 25; 10, p. 2; 40; 41, p. 1; 52, p. 1). A 1996 
88 

creel census documented that the section of the river that includes the area adjacent to the mill property 

received the highest rate of fishing pressure and had the highest catch rate of any section of the river (Ref. 

10, pp. 4, 7, 19, A-1; 11, p. 1). While this section also had the lowest percentage of fish kept (2 percent), 

the study still documented that over 1,000 fish were kept during the period of the survey (July 1, 1995 

through June 30, 1996) (Ref. 10, p. 7). The study also documented that anglers had concerns over the 

mill’s effect on water quality and fish populations on the river (Ref. 10, pp. 16-17). While fluctuating 

from year to year, data from the most recent angling pressure study (2009) shows an overall increase in 

the number of licensed anglers in the state (Ref. 9, pp. 15, 16).

The fish species kept for consumption include rainbow trout, brown trout, northern pike, and mountain 

whitefish (Refs. 10, p. 7; 40; 41). Crayfish are also caught and consumed (Ref. 11, p. 1). 

MFWP have established over two dozen formal river access sites on the Clark Fork, including the Deep 

Creek and Harper’s Bridge sites (both at river mile 200, approximately 2 miles upstream of Source No. 

3), and the Erskine site (stretching from river mile 192.5 to 190), approximately 3.5 miles downstream of 

the mill property boundary (Refs. 6, p. 1; 12, pp. 5, 12; Figure 1 of this HRS documentation record).

Anglers access the stretch of river adjacent to the mill from the upstream formal river access points, as 

well as via a road (South Side Rd.) that runs along the south side of the river across from the mill (Ref. 

40; Figure 2 of this HRS documentation record). In 2004, the mill reported that each year the number of 

people recreating on the river in the area of the mill continued to increase (Ref. 22, pp. 3, 22).

Most Distant Level II Sample (collected October 2011) 

Sample ID: SSSW10

Sample Medium: Surface water

Hazardous Substance: Manganese (dissolved)

Distance from the highest PPE: approximately 3.6 miles 

Sample ID: SSSE10 

Sample Medium: Sediment 

Hazardous Substance: 1,2,3,4,6,7,8-HpCDD

Distance from the highest PPE: approximately 3.6 miles 

Level II Fishery

Identity of 

Fishery

Extent of Level II Fishery 

(Relative to Highest PPE)

References

Clark Fork 

River

3.6 miles, as measured from the 

highest PPE on the Clark Fork 

River (i.e., the PPE from Source 

No.3), downstream to the colocated samples SSSE10/SSSW10

5, pp. 22, 68; 6, p. 1; 9, pp. 15-16; 10, pp. 4, 

7, 19; 11, p. 1; 12, pp. 5, 12; 22, p. 22; 40; 

79, p. 9; Tables 4A and 4B and Figures 3 

and 5 of this HRS documentation record 

4.2.3.3.1 Food Chain Individual 

As noted previously, an observed release of the hazardous substances manganese and 1,2,3,4,6,7,8-

HpCDD, which both have a bioaccumulation factor value of 500 or greater, is documented in a perennial 

surface water body that is a fishery (the Clark Fork River) (see Tables 4A and 4B of this HRS 

documentation record). The Clark Fork River is managed by the MFWP as a cold water fishery and is
89 

heavily used by anglers and other water-based recreationists (Refs. 9, pp. 1, 11, 13, 18, 22, 24, 25; 10, p. 

2; 40; 41, p. 1; 52, p. 1). According to the MFWP and a fishing outfitter on the Clark Fork, the portion of 

the Clark Fork River adjacent to the Smurfit-Stone Mill property is fished and the fish are kept and 

consumed (Refs. 6, p. 4; 11, p. 1; 12, p. 5; 40; 52, p. 1; Figure 1 of this HRS documentation record). The 

fish species kept for consumption include rainbow trout, brown trout, northern pike, and mountain 

whitefish (Refs. 10, p. 7; 40; 41). Crayfish are also caught and consumed (Ref. 11, p. 1). 

Sample IDs: SSSW05, SSSW06, SSSW08, SSSW010

Sample Medium: Surface water

Level I/Level II/Potential: Level II

Hazardous Substance: Manganese (dissolved)

Bioaccumulation Potential: 50,000 

Sample IDs: SSSE05, SSSE06, SSSE07, SSSE08, SSSE09, SSSE10

Sample Medium: Sediment 

Level I/Level II/Potential: Level II

Hazardous Substance: 1,2,3,4,6,7,8-HpCDD

Bioaccumulation Potential: 50,000 

Identity of 

Fishery

Type of Surface Water Body References

Clark Fork 

River

Large stream to river

(mean annual flow rate = 5,330 

cfs)

1, Table 4-13, p. 51613; 9, pp. 20, 78, 118, 

129, 138; 10, pp. 2, 7; 11, p. 1; 40; 41, p. 1; 

52, p. 1; 60; 71; Figure 1 of this HRS 

documentation record

As a portion of the Clark Fork River where fish are taken and consumed is subject to Level II 

contamination, this portion of the river is assigned a food chain individual factor value of 45 (Ref. 1, p. 

51638, and Section 4.2.3.3.1).

Food Chain Individual Factor Value: 45 

4.2.3.3.2 Population 

4.2.3.3.2.1 Level I Concentrations 

No Level I concentrations have been documented.

4.2.3.3.2.2 Level II Concentrations 

The Clark Fork River is evaluated as a Level II fishery. According to the MFWP and a fishing outfitter on 

the Clark Fork, the portion of the Clark Fork River adjacent to the Smurfit-Stone Mill property is fished 

and the fish are kept and consumed (Refs.11, p. 1; 40; 52, p. 1). The fish species kept for consumption 

include rainbow trout, brown trout, northern pike, and mountain whitefish (Refs. 10, p. 7; 40; 41). 

Crayfish are also caught and consumed (Ref. 11, p. 1). Specific information is not available on the annual 

production of fish caught in the Clark Fork River within the TDL. Therefore, the annual production for 

the water body is undetermined, but greater than zero because the Clark Fork River is a fishery (Refs.11, 

p. 1; 40; 52, p. 1). 
90 

Identity of 

Fishery

Annual 

Production 

(pounds)

References Human Food Chain 

Population Value (Ref. 

1, Table 4-18)

Clark Fork 

River

>0 1, pp. 51621, 51638, Sections 

4.1.3.3.2.2 and 4.2.3.3.2.2; 10, p. 7; 

11, p. 1; 40; 52, p. 1

0.03

Level II Concentrations Factor Value: 0.03 

4.2.4 Environmental Threat 

4.2.4.1 Environmental Threat – Likelihood of Release 

As was shown above in Section 4.2.1.3 of this HRS documentation record, an observed released of siteattributable contaminants is established for both the uppermost aquifer as well as the Clark Fork River.

Therefore, an observed release factor value of 550 is assigned for the watershed (Ref. 1, pp. 51629, 

51638, Sections 4.2.2.1.1 and 4.2.4.1).

Likelihood of Release Factor Value: 550 

4.2.4.2 Environmental Threat – Waste Characteristics

4.2.4.2.1 Ecosystem Toxicity/ Mobility/ Persistence/ Bioaccumulation

Table 6 below summarizes the ecosystem toxicity, mobility, persistence, and bioaccumulation potential 

factor values for each hazardous substance for which an observed release into the surficial alluvial aquifer 

has been established (Ref. 1, p. 51638, Section 4.2.4.2.1). As per Section 4.2.4.2.1.5 of the HRS, the 

substance with the highest ecosystem toxicity/ mobility/ persistence/ bioaccumulation potential factor 

value is used to assign the ecosystem toxicity/ mobility/ persistence/ bioaccumulation potential factor 

value for the watershed (Ref. 1, p. 51638, Section 4.2.4.2.1.5). Lead has the highest ecosystem toxicity/ 

mobility/ persistence/ bioaccumulation potential factor value of 5 x 107

. 

Ecosystem toxicity/ Mobility/ Persistence/ Bioaccumulation Factor value: 5 x 107
91 

Table 6: Ecosystem Toxicity/Mobility/Persistence/Bioaccumulation Factor Values for the Environmental Threat

Hazardous 

Substance

Source

No.

Ecosystem 

Toxicity Factor 

Value 

(Environmental) 

(Ref. 1, p. 51638, 

Section 

4.2.4.2.1.1) 

Mobility 

Factor 

Value*

Persistence 

Factor 

Value (for 

rivers)

Ecosystem

Toxicity/

Mobility/ 

Persistence 

Factor Value 

(Ref. 1, p. 

51639, Table 

4-29) 

Bioaccumulation 

Potential 

Factor Value 

(Freshwater)

(Ref. 1, p. 

51638, 

Section 

4.2.4.2.1.4)

Ecosystem

Toxicity/Mobility/

Persistence/Bioaccumulation 

Factor Values

(Ref. 1, pp. 51640-

51643, Table 4-30) 

References

2,3,7,8-TCDD 1, 2, 3 0 1 1 0 5000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-330

1,2,3,7,8-

PeCDD

1, 2, 3 0 0.0001 1 0 50000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-264 

1,2,3,6,7,8-

HxCDD

1, 2, 3 0 1 1 0 5000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-202 

1,2,3,4,6,7,8-

HpCDD

1, 2, 3 0 1 1 0 50000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-184 

Total-TCDD 1, 2, 3 0 1 1 0 50000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-328 

2,3,7,8-TCDF 1, 2, 3 0 1 1 0 50000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-332 

2,3,4,7,8-

PeCDF

1, 2, 3 0 1 1 0 0.5 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-268 

Arsenic 1 10 1 1 10 5000 5 x104 1, pp. 51601-51602, 

Table 3-9; 2, p. A-30 

Lead 1 1000 1 1 1000 50000 5 x107 1, pp. 51601-51602, 

Table 3-9; 2, p. A-224

Manganese 1, 2, 3 0 1 1 0 50000 0 1, pp. 51601-51602, 

Table 3-9; 2, p. A-232

Notes:* As per Ref. 1, p. 51601 (Section 3.2.1.2), all substances that meet the criteria for an observed release by chemical analysis to one or more aquifers 

underlying the identified sources are assigned a mobility factor value of 1.
92 

4.2.4.2.2 Hazardous Waste Quantity

The sum of the hazardous waste quantity values for Sources 1, 2 and 3 corresponds to a hazardous waste 

quantity factor value of 1,000,000 in Table 2-6 of the HRS (Ref. 1, p. 51591). Therefore, a hazardous 

waste quantity factor value of 1,000,000 is assigned for the ground water to surface water migration 

component of the surface water migration pathway (Ref. 1, Sections 2.4.2.2 and 4.2.4.2.2, pp. 51591, 

51592, 51644).

Hazardous Waste Quantity Factor Value: 1,000,000

4.2.4.2.3 Calculation of Environmental Threat – Waste Characteristics Factor Category Value

The hazardous substance lead associated with Source No. 1 (which has a ground water pathway 

containment factor of greater than 0 for the watershed) corresponds to an ecosystem toxicity/ mobility/ 

persistence factor of 1,000 and a bioaccumulation potential factor of 50,000 (Ref. 1, Tables 3-9 and 4-29; 

Ref. 2, p. A-224; Table 6 of this HRS documentation record).

(Ecosystem toxicity/ mobility/ persistence factor value) x (hazardous waste quantity factor value 

for the watershed):

1,000 x 1,000,000 = 1 x 109 

Subject to a maximum of 1 x 108 = 1 x 108 (Ref. 1, p. 51644, Section 4.2.4.2.3) 

(Product above) x (bioaccumulation potential factor value for the substance)

(1 x 108

) x (50,000) = 5 x 1012 

Subject to a maximum of 1 x 1012 = 1 x 1012 (Ref. 1, p. 51644, Section 4.2.4.2.3) 

The waste characteristics product of 1 x 1012 corresponds to a waste characteristics factor category value 

of 1,000 in Table 2-7 of the HRS (Ref. 1, p. 51592, Section 2.4.3.2).

Waste Characteristics Factor Category Value: 1,000 

4.2.4.3 Environmental Threat - Targets 

4.2.4.3.1.1 Level I Concentrations: 

No Level I concentrations have been documented. 

4.2.4.3.1.2 Level II Concentrations: 

Sensitive Environments (Habitat known to be used by the Federally-Designated Threatened Bull Trout)

Level II concentrations of dissolved manganese have been documented in the Clark Fork River.

According to the MFWP and the U.S. Fish and Wildlife Service, the Clark Fork River is habitat known to 

be used by the federally designated threatened native bull trout, including the area of the Clark Fork 

adjacent to the Smurfit-Stone Mill (Ref. 5, pp. 971, 975-976, 978, 980; 6, pp. 1-4; 7, p. 2; 8, pp. 1, 10, 13-

15; 10, pp. 7, 20; 11, p. 1; 12, p. 3; 13, pp. ix, 1, 2, 3, 10, 23, 24, 125; 14, pp. 1, 6; 15, pp. 1-4; 20, p. 2; 

40; section 4.2.1.3, Figure 5 and Table 4A of this HRS documentation record). This area is subject to 

contaminated ground water from Source Nos. 1, 2, and 3 migrating to surface water. Surface water 

samples collected from the river adjacent to the mill property during 2011 show concentrations of 

dissolved manganese meeting HRS observed release criteria (Ref. 5, pp. 971, 975-976, 978, 980; section 

4.2.1.3 and Table 4A of this HRS documentation record). The sampling locations are shown in Figure 3 

of this HRS documentation record. 
93 

Therefore, actual contamination is documented, and the target sensitive environments are evaluated for 

actual contamination, within the zone of actual contamination. 

Level II Sensitive Environment targets

Sensitive 

Environment

Distance from PPE 

to Nearest Sensitive 

Environment

References Sensitive Environment 

Value (Ref. 1, Table 4-

23)

Habitat known to 

be used by Federal 

designated 

threatened Species 

(bull trout) 

0.0 mile 6, pp. 1-4; 7, p. 2; 8, pp. 1, 

10, 13-15; 10, pp. 7, 20, A1; 11, p. 1; 12, p. 3;13, pp. 

ix, 1, 2, 3, 10, 23, 24, 125; 

14, pp. 1, 6; 15, pp. 1-4; 20, 

p. 2; 40

75

Sum of Sensitive Environments Value: 75 

Level II Concentrations Factor Value: 75

(Ref. 1, p. 51644, Section 4.2.4.3.1.2, p. 51624, Table 4-23) 

Additional Supporting Documentation 

Sensitive Environments 

In 2007, the bald eagle was removed from the Federal List of Threatened and Endangered Species due to 

its recovery. The USFWS will continue to monitor the status of the bald eagle over a 20-year period, at 5-

year intervals (Ref. 74). The portion of the Clark Fork River immediately adjacent to the Smurfit-Stone 

Mill property has been listed as a Wildlife Protected Area by the Northwest Power and Conservation 

Council (an entity created by the U.S. Congress and authorized in the Northwest Power Act of 1980), as it 

contains bald eagle nesting territory, is a bald eagle winter concentration area of high density, and is a big 

game critical wintering/spring area (Ref. 8, p. 12; Figure 2 of this HRS documentation record). 

Wetlands frontage

Approximately 1.9 miles of riverside palustrine wetlands (both emergent and scrub-shrub) have been 

provisionally mapped within the area of the Clark Fork River subject to actual contamination (Refs. 27; 

71, p. 2; Figures 1, 2 and 3 of this HRS documentation record). While palustrine emergent and scrubshrub wetlands are presumed to be HRS-eligible, field verification of these wetland areas has not 

occurred. As such, wetlands frontage has not been included in scoring for the site.

4.2.4.3.1.3 Potential Contamination

There are targets subject to potential contamination associated with the surface water bodies downstream 

of the zone of contamination and within the TDL, including additional bull trout habitat and wetlands; 

however, as the actual contamination score is sufficient to score the environmental threat, potential 

contamination is not scored (Refs. 1, Section 4.2.4.3.1.3; 6, pp. 1, 4; 10, pp. 7, A-1).

Potential Contamination Factor Value: Not Scored